Land Resource Study of Hodeidah Green Belt Area. Field … · 2017. 11. 27. · fig. 1 Location map of the study area 3 fig. 2 Generalized geological map of Yemen 4 fig. 3 Flodeidah:

FOOD AND AGRICULTURAL ORGANIZATION OF THE, UNITED NATIONSENVIRONMENTAL RESOURCE ASSESSMENT FOR RURAL LAND USE PLANNINGGCP/YEM/02 I/NET Field Document 12

AF 6 0)

r

LAND RESOURCE STUDY OF HODEIDAHGREEN BELT AREA

RENEWABLE NATURAL RESOURCES RESEARCH CENTREAGRICULTURAL RESEARCH AND EXTENSION AUTHORITY

MINISTRY OF AGRICÚLTURE AND IRRIGATIONDHAMAR, REPUBLIC OF YEMEN

1997

FOOD AND AGRICULTURAL ORGANIZATION OF THE UNITED NATIONSENVIRONMENTAL RESOURCE ASSESSMENT FOR RURAL LAND USE PLANNINGGCP/YEM/021/NET Field Document 12

LAND RESOUR CE STUDY OF HODEIDAH GREEN BELT AREA

by

Mohammed Hezam Al-MashrekiAREA Senior Soil Surveyor

RENEWABLE NATURAL RESOURCES RESEARCH CENTREAGRICULTURAL RESEARCH AND EXTENSION AUTHORITY

MINISTRY OF AGRICULTURE AND IRRIGATIONDHAMAR, REPUBLIC OF YEMEN

1997

ABSTRACT

In this report the results are presented from the soil survey carried out in the Green Beltarea around Al-Hodeidah. This report covers the relevant parts of the Tihama coastal plain,including part of the wadi Siham alluvial plain. A soil map, land use map, vegetation map andphysiographic map, all at a scale of 1 : 50.000, were prepared. The total area covered isapproximately 15200 ha, situated in a half circle around Hodeidah city.

The soils are in general homogeneous with little pedogenetic development, and variabledegrees of salinity and sodium content. Apart from the more sandy soils that generally coverthe coastal plain, the flood irrigated alluvial parts have more loamy textures. These soils havea low organic matter content, moderate fertility and a moderate internal drainage. The qualityof groundwater used for irrigation is poor with high levels of sodium.

The soil map indicates that about 25% of the area is occupied by active duneland, andanother 35% consists of flat and hummocky sandy areas affected by shifting sands. These areasare used mainly for grazing. A considerable part of the survey area (about 40%) is used fortraditional rainfed and irrigated farming by mainly small scale farmers.

..Basecl on the above findings it is recommended that a development plan should considerthe three different environments

The cluneland areas where afforestation for sand stabilisation is urgently needed.

The relatively flat sandy areas which are suitable for grazing can be planted with droughtresistant tree species which are suitable for forage, while some parts, depending on wateravailability, could be turned into plantation forests.

The agricultural latid requires agro-forestry to provide fruit trees and fuelwood trees tolocal farmers, and shelterbelts to protect crops against the strong prevailing 1,vinds.

Treated sewa2.e water from the nearby sewage plant could be used for the sandy landsand dune lands to irrigate selected trees tolerant to salinity (e.g. Azadirachta indica).Underground water should be used mainly for irrigation of vegetables and fruit trees. In thefarming areas, attention should also be paid to introducing special management practices, suchas crop rotations, to increase yields and protect the soils. The development of recreation areasand protected .natural areas Within the Green Belt should also be cc.msiderecl. However, thedevelopment of infrastructure and built-up areas inside the Green Belt must be strictly controlledto reduce the hazard of land degradation.

ACKNOWLEDG.MENTS

The author would like to express his gratitude to Dr. A. Bamatraf, General DirectorAREA, for his concern and support towards this study. Many thanks are extended to Mr. O.Bafadel, National Project Director, Dr. A. liaicler, Technical Director, and Mr. Wen, ChiefTechnical Adviser, for their administrative and technical support. The latter is also thanked forhis 'very thorough editing of the text. i would further like to extend tha.nks to Mr. L. Al-Asbahi,who contributed in the fieldwork, Messrs. A. An-Nasiri and F. Al-Kadasi in the cartographicsection, M. Abdulwasa in the climatic section and M. Al-Rakhami in the administration office,together with all other colleagues who provided assistance to produce this study.

Many thanks go to Dr. El-Abbas Doka, Land IZesource Expert, for supervising this studyand for his continuous guidance and support. I would like also to extend thanks to the laboratorystaff headed by Dr. A, E. Fadl for their efforts to analyze the soil and water samples

II

TABLE OF CONTENTS

ABSTRACT

ACKNOWLEDGMENTS

INTRODUCTION 1

Chapter 1 ENVIRONMEN'T ...... . . .

1.1 Location1.7 General characteristic of the area 21.3 Geology 2

1.3.1 Aeolian deposits1.3.1.1 Loess1.3.1.2 D LI nes 2L3.1.3 Fluvial deposits ti

1.4 Main land units 5

1.4.1 Alluvial plain 51.4.1.1 Wadi floors and channels 61.4.1.2 1..evees 61.4.1.3 Wadi terraces 6

1.4.2 Aeolian sand plain 61.4.3 Alluvio-marine platform 6

1.5 Vegetation 71.5.1 Man's influence on the vegetation of the Tihama 7

1.6 Land use 81.6.1 Nlain land use types 8

1.6.1.1 Arable farming 81.6.1.2 Grazing land 8

1.6.1.3 Dunes 91.6.2 Domina t land -utilization types 9

1.6.2.1 Irrigated cereals (small sized farms of 2-5 ha) 91.6.2.2 Irrigated cereals (medium sized farms 10-50 ha) 91.6.2.3 Irrigated vegeta.bles 101.6.2.4 Irrigated COLtOrl and sesame 10

L7 Water resources 101.8 Cl mate 10

1.8.1 Rainfall in the Tihama 15

1.8.2 Rainfall distribution 15

1.8.3 Temperature 161.8.4 Evapotranspiration 16

1.8.6 Other directly observed meteorological parankqers 16

Chapter 2 METHODS 212.1 Photointerpretation2.2 Fieldwork 21

2.3 Laboratory analysis methods 21

Chapter 3 SOILS 213.1 Origin of the soil3.7 Soil profile characteristic and processes

3.2.1 Soil texture and stratification 233.2.2 Depth 243.2.3 Colour 24

3.3 Taxonomic soil classification of the study arca3.3.1 Diagnostic horizons 953.3.2 Entisols 263.3.3 Addis°Is 263.3.4 Soil moisture regime 263.3.5 Soil temperature regime 27

3.4 The soil map 973.4.1 The soil legend

Chapter 4 LAND SUITABILITY CLASSIFICATION 304.1 General 30

4.1.1 Structure of the suitability classification 104.1.1.1 Land suitability orders4.1.1.2 Land suitability classes 31

4.1.1.3 Land suitability subclasses4.1.2 Summary

4.2 Classification criteria 334.2.1 Soil texture 334.2.2 Soil depth 344.2.3 Salinity 144.2.4 Alkalinity 344.2.5 Topography. 35

4.3 Classification tables 35

Chapter 5 CONCLUSIONS A.ND RECOMMENDATIONS 395.1 Conclusions 395.2 Recommendations 40

REFERENCES 41

LIST OF FIGURES

fig. 1 Location map of the study area 3

fig. 2 Generalized geological map of Yemen 4

fig. 3 Flodeidah: Precipitation and evapotranspiration graphs 1983-1990 13

fig. 4 Hodeidah: Precipitation and ETOfig. 5 Climatic zones in Yemen 19

iv

UST OF TABLES

table l

table 2table 3table 4table 5table 6table 7

table 8table 9

table 10

APPENDICES

Appendix l Analytical methodsAppendix 2 Soil profile descriptions and analytical dataAppendix 3 Water analytical dataAppendix 4 Map 1 Soil map (semi-detailed)

Map 2 Physiographic mapMap 3 .Land use mapMap 4 Vegetation map

Climatic data for a Flodeidah (1983-1990) I I

Average climatic data for Hodeidah (eight years) 17Area measurement of soil mapping. units. 28Soil mapping unit description 29Example of structured land suitability classification. 33Land suitability for irrigated agriculture 35Climate, soil and water requirements for some selected woodland speciesunder miffed conditions 36Land suitability classes for selected woodland species in the study area 36Climate, soil and water requirements for arable crops, vegetation and treespecies under irrigation 37Land suitability classes for arable crops and tree species cultivatedunder irrigation 38

INTRODU CTI ON

This study was requested by FAO Urban Forestry Tel) Project with the objective_ ofassessing the environmental resources in a semi-circular belt around Hodeidah for theirsuitability with regard to the establishment of a Green Belt of vegetation to protect the city andthe surrounding villages against sand encroachment. Senior soil surveyor Mr. MohammedHezam Al-Mashreki was assigned by the Renewable Natural Resources Research Centre,supported by FAO's Environmental Resources Assessment For Rural Land Use Planning Project(GCP/YEM/021/N ET), to carry out this study and write the final report.

The aims of this study are

identification and location of main types of soils and map there distribution.Characterize the soils in terms of chemical and physical properties.Determine suitability of the different soils for the development of vegetation for theGreen Belt.Characterize water resources and their suitability for irrigation.Identify and map the present land use and land cover.

The development of the Green Belt around Hocleidah is meant mainly asenvironmental protection for

Controlling sand encroachment.Utilize the large amounts of water from the sewage treatment plant forirrigating the Green Bel t.Benefit that can be obtained from the existence of the Green Belt are its use as arecreational area for the residents of Hodeidah, and as a landscape element that will add

more beauty to the scenic view of the city.

The field study was carried out in three phases

Exploratory SLUdy covering all aspects of the study (soils, vegetation, land use, water

resources).Semi-detailed for soil survey study to identify the main mapping units anddescribe the properties of their components.Socio-CC01101TliC study to identify the different farming systems and tocharacterize the dominant ones.

The -fieldwork was started On 16 September 1.996 and was completed after one and half

month.

The survey area is that part of the Tihama coastal plain which lies between UTIYI gridlines 1635000m-1649000mN and 280000m-293000mE (14°40'48" - 1454'24" N and 42'5642"-43'0400" E), surrounding Hodeidah city (see figure 1). It starts from the coast at about 6.5km north of Hodeidah along the road to Jayzan, and continues south east, crossing the Sana'a -

.Hodeidah road at km 16 and extending in south west direction towards the coast south ofHodeidah, thus making a hall circle around the city. The Width of the area is about 5 km in mostplaces, and the whole area encompasses about 15,200 ha.

1.2 GENERAL CHARACTERISTIC OF THE AREA

The survey area is shown on figure 1, and in greater detail on the physiographic map(Appendix 4). It cotnprises an extensive, largely featureless sedimentary coastal plain, with analluvial plain cutting through it, and sloping gently towards the Red Sea. In the north-east, closeto the sea, some variation in landscape is provided by extensive though discontinuous expansesof sand dunes, mostly longitudinal and barchans. Soil distribution, current land use and micro-relief in the southern part of the study area have been strongly influenced by the practice, overmany centuries, of flood irrigation from 'Wadi Siha.m.

1.3 GEOLOGY

Chapter I ENV RONMENT

1.1 LOCATION

According to studies done by Geukens (1966) and Grolier and Overstreet (1978), theHodeidah coastal plain lies within the Quaternary alluvium deposits, which have been dividedon the basis of their mode of transportation into wind-laid (aeolian) and water-laid (fluvial)deposits. A generalized geological map is shol,vn in figure 2.

1.3.1 Aeolian deposits

1.3.1.1 Loess

Loess deposits are found in areas where mountains present a barrier to the wind,causing it to slow dovn and drop its sediment load. The loess of Yemen probably originatedin the Rub Al-Khali to the northeast., the direction of the prevailing winds. Many of the loessdeposits, particularly in the inter-montane plains, have been reworked by alluvial processes.Some authors have indicated that loess deposits occur also in Tihama coastal plain.

1.3.1.2 Dunes

In the survey area, round sand dunes are found primarily to the north and east ofHodeidah where the ground is level (mapping units C223, C222, C221, C144). Barchan andlongitudinal dunes are found particularly on units C122 and C1.11, indicating that sand supplyis the limiting factor of dune formation. The source of the sand is probably the wadi beds and

2

Fig. I Location map of the study area

alluvial fans, which receive sand from wadies emanating from the mountains. The great sandseas of the Rub Al-Khali are outside of the survey area.

3

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Figure 2 Generalized geological map of Yemen(units Qal and Qel occur in the study area)

4 0,,

GENEtIALIZED

GEOLOGY MAP

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1 ,,,,,, r, 0, Olwem

Source: King Jack W 11, Abu Ghanem (1983)

PC

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LEGEND

LIipto-CamOrian shiold

Wapd oandstono

JK u: Arntan limootonainri Kontan analo

LiKt'

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..........

Taltwan and Moci-7..oandotonuo

Yornon volcar,c

Granite, Intrueone

ilocont basalt*

011011 000031101

1.3.1.3 Fluvial deposits

Alluvial plains form broad, flat areas of low relief in the study area. The processesof sediment deposition which form alluvial plains are similar to those which form wadi beds.The sediments, however, are generally finer in texture than those in the active wadi beds. andare spread over a much larger area. The source of .the sediments is the weathering debris fromthe highlands mixed with alluvial loess.

The coastal plain consists of sedimentary deposits which, away from the mountainfront, are at least 200 ni thick. The subsurface geology is basically a continuum with two broadfacies based on grain-size. The deposits on the alluvial plain are finer-grained and some whatbetter sorted, coarse pebbly sand, gravels and pebble beds pass westwards into medium sandswith subsidiary pebbly sands, gravel, silty sand and even silty clays.

The deposits are rather uniform 1,vith depth and exceed 150 cm. The main wadi Sihamvalley is floored by bouldery and cobbly alluvium, up to several tens of meters thick. flankedby a series of alluvial terraces, rising to at least 15 in above the wadi bed. North and north-eastof Hodeidah, and particularly towards -the coast, superficial sand dunes are prominent, stabilizedin part by sparse vegetation. Grey lagoonal clay, probably of marine origin, and overlain bya discontinuous veneer of aeolian fine sand, form a low raised beach in the level coastal areasto the south of wadi Siham.

1.4 MAIN LAND UNITS

Three main physiographic units have been recognized, viz.:

Alluvial plain.Aeolian sand plainAlluvio-Marine platform

The text on map 3 (appendix 4) indicates the relationship between these, units and theirdistribution.

1.4.1 Alluvial plain

The alluvial plain of wadi Siham lies to the east of :1-Iodeidah, the transition with theeolian and marine deposits being marked by a slight decrease in slope, a more pronouncedsurface relief and the increasing influence of windblown sands. To the south-east the plainbordered for the most of its length by the main eastern wadi Siham channels. The plain alsoreceives and disperses flow from the southern channel through a complex irrigation network,which now mostly relies on pump irrigation, but apparently vas subject to regular spateirrigation in the past. Aeolian erosion and deposition affect- the entire area and is locall),,' severe.Natural vegetation, which in many places flanks former wadi channels, also stabilizes a micro-rel ie f of aeolian hummocks.

5

A further physiographic subdivision can be made into:

Present wadi floors and channelsLeveesWadi terraces

1.4..1.1 Wadi floors and channels

The textural composition of the sediments in the present stream beds of Wadi Jailer.(Siham) varies from rounded gravel and stones at the apex of the fans to sands in the central partand Lo well sorted silts in the braided channels forming .the southwestern fringes of the alluvialsystem. Consequently the present wad deposits rise above the surrounding olcler alluvial plain.

1.4.1.2 Levees

Levees are embankments gradually built by the s,vadi along their channels. leevees dooccur in the alluvial system of wadi Siham. The levees rise 1-2 m above the level of theadjacent subrecent wadi terraces, towards which they slope gradually on the side away from theriver. Consequently they have a good external drainage. They are generally coarse textured(sands), but clue to long term spate irrigation often overlain by a 0.5 to L m thick layer of silts.

1.4.1.3 Wadi terraces

The wadi terraces include recent and sub-recent alluvium of wadi Siham. The mostrecent terraces are found along the wadi beds, up to 1 ni above the present base levels. Theyare flooded regularly. Their textural composition roughly follows that of the wadi floors, withcoarse textured material in .the eastern parts, which becomes more silty towards the southwest.Only some of the higher, more silty terra.ces are under cultivation.

The subrecent terraces are higher and generally separated from the wadi beds by leveesand wadi incisions. South of wadi Siham these terraces have been built on top of older alluvialdeposits, and have a moderate slope towards the wadi (2-5%), gradually merging into thealluvial plain. Sedimentation on these subrecent terraces has been clearly influenced by spateirrigation, as the upper layers of parent material consists inanity of well sorted silts.

1.4.2 Aeolian sand plain

This occupies much of the land to the north and north-east of Hodeidah, between theJayzan and Sana'a roads. Although mostly bare of vegetation, the lower dunes are partiallystabilized by a sparse ground cover. Higher dunes are mostly active and mobile, contributingin creating barchan and longitudinal dunes. The dune area is both depository and a source ofwind-blown sand.

1.4.3 Alluvio-rnarine platform

This is the level coastal arca where, medium and fine textured alluvio-marine sedimentsare overlain by a discontinuous cover of aeolian sand derived from shoreline deposits. With the

6

exception of the alluvial part of the study area, most of the remainder is underlain by thisplatform.

1.5 VEGETATION

The different plant formations and plant communities in the Tihama are not so muchconnected with climatic differences as with other important ecological factors such as elevationabove the water-table, water salinity, texture ancl mobility of sands. Where the tidal range ofthe Red Sea is protected by sand bars, the shallow water lagoon is the habitat for a Mangrove(Avicennia marina) woodland. A large zone, sometimes up to 5 km inland, is usually sterile,due to its high salinity. Only periodically better drained places may be covered by a fewhalophytic plants like Suaeda frtaicosa and, when topped with thin \,vind-borne sand-layer bygrasses. This is a very poor herbaceous and half-woody salt swamp formation.

The next plant formation further inland may be called a sub-desert shrubland withhalophytic succulents. Here the most important community is a salt-bush community with,Sttaeda monoica, on slightly elevated but still very compact marine deposits with high salinity,situated ,just above the current flood level. These deposits are often overlain by aeolian sand andthe Saaedo bushes form small hillocks reaching one meter high and leaving space %,yhere annualslike Zygophyllum simplex appear after heavy rainfall. Vast stretches of land can be covered bythis community. The plant cover may reach a surprising density of more than 50%.

The vegetation of the adjacent sub-desert plain shows a mosaic pattern, depending onsuch factors as topography. texture, depth and tnobility of the surface deposits and differentforms of human interference. Many different plant communities here belong to three plantformations. Among this the first and most important one is a droug,ht deciduous mixed dwarf-shrubland with deciduous and evergreen dwarf-shrubs, and only a few microphyllous or leaflessshrubs with green stem, With tussock-forming grasses, succulents and other life-forms.

On a few mobile dunes, where the wind is the main agent for deposition and deflationgood sand binders like the grasses Panicum turgidam and Odyssea macronata as well as thedwarf-shrub lndigofera ,spinosa can be found. On the valley bottom between the higher ancllarger dunes phytogenctic mounds and hillocks are very common. The evergreens Cadabarotandifolia and Cadaba glandalosa collect the moving sand With their leaves ancl branchc,..s,forming, hillocks up to two meters hiEh. They are often associated With SOlTie succAllents likethe Euphorbia triacaleata. After rainy periods, on silty and fine sandy deposits around thehillocks, dense ephemeral growth of Corcharas depressus. Fagonia indica, Eapharbia indica,Tephrosia ploporea, .Dipterygium gialiC11171, and Schouwia parporea is fairly common. Avegetation map of the study area is included in Appendix 4.

1.5.1 Man's influence on the vegetation of the Tihama

At some time in the past a fairly dense forest, or at least open \voodiand, of Acaciaehrenbergiana and Acacia tortilis was the dominant natural vegetation of the Tihama (DHV,1990) except on the coast near Salt pans. TOday 1710St Of the trees are gone and much of the ata--.ais cultivated either by flood irrigation or by modern pump irrigation.

7

One positive effect of the human influences is the establishment in some places of atree vegetation along the edges of the many terraces lining the wadi. However, no vegetationwas planted along the terraces in some 'parts of the Wadi bottom, as these are prone todestruction by large floods which happen once every one to two decades.1.6 LAND USE

The area with permanent agricultural fields, mostly dominated by pump irrigation,starts from the Hodeidah-Sana'a road, going towards the south of Hodeidah cuy until QuzaatAldubal and Alselah villages. The fields consist of rich alluvial soils capable of producingsevera] crops per year under irrigation. Wadi Jailer is particularly favourable for intensiveagriculture. It should be noted that this area is now no longer affected by floods (probably dueLo a higher water use in the upstream parts of the wadi) and hence pumped groundwater is beingused increasingly. In fact, the groundwater used for irrigation is saline and has a highconcentration of sodium, which imposes a great risk to the soil quality and negatively affectscrop yields. For more details on the land use see the land use map in appendix 4.

On regularly irrigated fields, numerous crops are cultivated, including vegetables liketomatoes, beans, watermelon, and other crops such as sesame, cotton, tobacco, maize anddifferent local sorghum species.

The proposed Green Belt area is sparsely inhabited by villagers who live scattered ingroups of small huts. All large villages or towns are located outside the study area. Many oftheir inhabitants commute to Hodeidah for daily paid jobs. It is understood that all existingagricultural land will remain as part of the Green 13elt, and will benefit from the developmentof the Green Belt to protect them from sand encroachment and sand storms.

1.6,1 iVlain land use type

The three main types of land use found in the study area are

Arable landGrazing landDune land (unused)

1.6.1.1 Arable farming

The rnain arable farming areas are located at time southern part of the Green Belt.These areas generally consist of irrigated land cultivated by cereals, vegetables and cotton.Spate or flood irrigation is practised in years of high floods. The dominant size of holdingsvaries .from small to large (5-30 ha) and is owned by local farmers. The smallholder type ofagriculture is mainly traditional subsistence farming with very limited production for markets,while the larger landowners either rent out their land to sharecroppers or produce for the market.

1.6.1.2 Grazing land

Grazing land is located on both sides of the wadi Siham valley (north and the south),occupying large part of the study area. It is in general covered by natural grasses and shrubs.After the harvest some of the arable lands are used for grazing, especially around villages.

8

Camels, goats, sheep a.nd cows can normally be found grazing all over the area. It should benoted that the number of animals living within the Green Belt arca is not that much, but largenumbers of them are daily brought in from outside this area. These grazing lands are alsoowned by local farmers.

1.6.1.3 Dunes

The active or mobile dunes occupy a large part of the study arca, starting from Al-Baidah at the Flodeidah-Jayzan highway in the north and continuing to the eastern part of thestudy area, bordered by the Hodeidah-Sana'a highway. In fact 0A70 types of dunes can berecognized: longitudinal and barchan dunes. The area covered by these dunes is not suit-able foragriculture.. Some kind of shrubs and dwarf shrubs grow in the interdune depressions. It is

believed that this area used to be a sand plain, but due to deforestation a major part becamesusceptible to sand displacement. The ensuing intensive sand blowing process lead to theformation of recent mobile dunes. This is a continuous process, resulting in the dunes nowe,ncroaching onto urban areas and their infrastructures.

1.6.2 I)oniinani land -utilization types

Land uti ization types are a refined kind of land use, with special emphasis onmanagement aspects of the land use, and suitable for land evaluation purposes. The main landutilization types in .the study are described below.

1.6.2.1 Irri.,,ated cereals (small sized farms of 2-5 ha)

Irrigated sumiller cereals (sorghum and millet), grown for about 130 days undergravity irrigation relying on pumped grounds,vater. Smallholder farms of 2-5 ha owned by onefarmer, but some parts inay be used for sharecropping (subsistence farming). -Family and hiredlabour work with traditional equipment. There is a limited application of green manure only,and no pesticides are used. Livestock (goat, sheep, cows, and camels) are kept for meat andmilk. Oxen are used for traction and donkeys and camels for transportation. Surplus grainsfrom smallholder farms are sold in local markets. The stalks of sorphum and ni illet are usedfor fodder, part of it being sold at the farm gate. Cereal yields vary from 0.3 to 0.5 ton/ha.These farms are affected by sand blowing which covers young plants at early stages of growth.Wadi terraces cultivation is much affected by this problem.

1.6.2.2 Irrioatecl cereals medium sized farms 10-50 ha)

Crops and their irrigation are similar to those grovm on small sized fartns. rim,vever,inedium sized farms are mostly cultivated by sharecroppers, the ow-ner receiving one quarter orone third of the produce. Green manure and pesticides are widely used. Cereal yields are onlymarginally better than those attained at smallholder farms. Apart from farm managementoperations, which are mainly done by tractors, hired labour works With traditional equipment.Livestock reared on the farm is sold in local markets (much of it being bought for transport tothe cities, including Sana'a). Fodder is also largely sold in local markets.

1.6.2.1 Irrigated vegetables

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Limited acreage of irrigated vegetables (e.g. okra, cucumber, pepper, tomato. squash,sweet melon, iew's mallow, cabbage etc.) are grown by most farmers for domestic consumption,but produce from medium sized farms is sold in local markets. The growing period forvegetables is about 7-9 weeks. Also water melon and sweet melon are commonly cultivated inboth small and medium sized farms. The farmer sells it direct from the field OF in the localmarket. Pesticides are used in vegetable cultivation.1.6.2.4 Irrigated cotton and sesame

Irrigated cotton and sesame are found mainly in an areas with medium and large sizefarms in the downstream part of the alluvial plain. At its present price, cotton is of little interestto the farmers, mainly on account of the excessive variable costs in relation to the value of thecrop. Sesame is a crop that is well suited to the irregularly flooded areas, since it requiresrelatively little water. At present price levels of sesame are acceptable. llowever, these priceare somewhat artificial since the sesame imported by industry is much cheaper, and substituteproducts (palm oil in particular) are retailed at 11111Cli lower price.

1.7 WATER RESOURCES

Over the last few years there has been a considerable inc,rease in the use ofgroundwater. For agriculture this resource was hardly exploited at all in the past.

With regard to water quality, the American "Riverside" water classification providescriteria for assessing the suitability of groundwater for agriculture, based on a combination ofthe following factors (Appendix 2 provides some information on the water quality in the surveyarea)

- Total concentration of soluble salt, measured by electric conductivity (EC).- Sodium content in relation to calcium and magnesium content.

Water in the wadi Siham plains is the factor limiting agricultural production whenrainfed agriculture is practised. In general, where a possibility for irrigation exists, yields arelimited by production -factors such as crop and soil management and irrigation techniques, andinadequate use of improved seeds, fertilizer and pesticides. Such that the quantities of water tobe applied and the state of technical advance of agriculture must be considered as going handin hand. For this reason, given the low level of farm management in the study area, it is

expected that yields will remain much lower in the foreseeable -future than those correspondingto the genetic potential of the plants cultivated. Under these conditions, it would be better tospread .the scarce water resources over a much wider area of crops, receiving a water allocationconsiderably lower than what is necessary to compensate for the potential evapotranspirationloss, as a large area with a loy yield per ha will still produce more that a smaller are.a with onlya marginally better yield.

1.8 CLIMATE

The Tihama has a tropical arid climate. The mean tempera.ture is very high (30°C)with inconsiderable seasonal fluctuation. Absolute minima and maxima, however, range

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Table 1 Cflmatic data for Hodeidah (1983-1990)

immoRH(%) 112 119 118 118 Ili 119114.13

Tmean (°C) 25.6 27.1 28.5 30.5 33.3 34.3 33.1 32.6 30.5

stationlatitudealtitude

year

station Hodeidah ( Airport ) Jan Feb MarJ Apr May Jun Jul Aug Sep Oct Nov Declatitude 14.76 Tmax (°C) 28.0 28.3 29.3 34.1 33.8 35.1 35.6 34.6 35.2 33.0 30.8 29.9altitude ' 11 Tmin (°C) 19.6 19.1 22.6 23.8 27.7 28.3 28.8 28.1 27.3 23.1 20.6 20.1

RH (%) 75 76 77 74 74 73 72 74 75 77 86 89year 1984 windrun (km/day) 449.3 614.4 495.4 518.4 549.1 499.2 483.8 414.7 460.8 403.2 433.9 407.0

sun (hour/day) 8.2 9.3 9.4 10.2 8.7 4.4 5.5 8.6 8.0 9.8 9.7 9.2precipitation (mm/month) 2.3 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0ETO (mm/month) 126 142 155 191 195 173 185 188 181 157 114 970.5 ETO (mm/month) 63 71 77 95 98 87 92 94 91 79 57 48Tmean (°C) 23.8 23.7 26.0 29.0 30.8 31.7 32.2 31.4 31.3 28.1 25.7 25.0

station Hodeidah ( Airport ) Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Declatitude 14.76 Tmax (°C) 29.6 29.0 31.3 33.1 34.4 36.8 36.8 37.6 37.1 36.3 32.8 39.8altitude 11 Tmin (°C) 19.6 20.7 22.6 26.6 27.3 27.8 28.1 28.5 27.0 24.5 23.2 19.2


sun (hour/day) 8.3 8.2 9.1 8.5 8.7 7.7 7.7 7.2 7.1 9.2 9.4 8.5precipitation (mm/month) 0.0 0.0 4.0 0.0 9.9 0.0 0.0 0.0 0.0 0.0 0.0 0.0ETO (mm/month) 96 118 128 142 154 160 162 150 145 155 127 1180.5 ETO (mm/month) 48 59 64 71 77 80

,81 75 73 78 63 59

Tmean (°C) 24.6 24.9 27.0 29.9 30.9 32.3 32.5 33.1 32.1 30.4 28.0 29.5station Hodeidah ( Airport ) Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Declatitude 14.76 Tmax (°C) 27.5 29.6 30.8 33.2 35.2 35.2 38.3 35.6 36.7 34.0 32.5 30.9altitude 11 Tmin (°C) 18.4 22.4 23.3 25.7 27.5 30.1 29.5 30.5 27.2 24.8 22.6 20.9


sun (hour/day) 7.2 7.9 7.6 8.1 9.8 7.7 7.2 7.1 7.7 9.7 9.8 8.7precipitation (mm/month) 0.0 8.5 12.0 15.0 0.0 0.0 4.0 0.0 0.0 0.0 0.0 3.7ETO (mm/month) 93 104 111 123 168 163 170 160 183 136 126 105

0.5 ETO (mm/month) 46 52 55 62 84 82 85 80 92 68 60 52

Tmean (°C) 23.0 26.0 27.1 29.5 31.4 32.7 33.9 33.1 32.0 29.4 27.6 25.9

Hodeidah ( Airport ) Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec14.76 Tmax (°C) 31.3 31.8 32.8 34.5 37.4 38.2 39.5 37.9 38.1 36.1 32.0 29.8

19.9

25.5 24.9

Table 1 Climatic data for Hodeidah (1983-1990)

s ation Hodeidah ( Airport Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Declatitude 14.76 28.9 29.5 31.6 34.4 36.0 MILEBNIMENI 37.4 34.4 31.6MEE 29.6

20.0altitude

MIMIINIMIIIIMIll1111.1.111111.11.IIIMMIMIIIIIIIIII111111111111111.1

1987

uhIr1IwRH (%)

18.8 20.0 24.6 27.4 29.0 29.9 29.5 29.1 27.081 86 85 78 82 82 83 79 80 76J 79

windrun (km/day)sun (hour/day)precipitation (mm/month)ETO (mm/month)

583.7 576.0 487.7 399.4 844.8 384.0 361.0 IMMEID 337.9 399.4 399.4 430.1ENNUI8.9 9.1 9.1 8.8 7.6 INIMIEI 6.6 8.0 9.9 10.0

0.8 0.0 0.0 2.0 0.0 0.0 0.0 0.0 0.0 0.0mffle 1.9120jj 114 130 168 176 162 163 167 169 174

station

11.1.11111.11.11.MIMMIIIMMEIMMI

Hodeidah

0.5 ETO (mm/month)

( Airport )

59 65 84 88 81 81 84 85 87 78 60

23.9 24.8 28.1 29.3 30.9 MEE 33.6 33.6 MIN 30.7 26.7 24.8Jan Feb ME= Apr IIIMMINIEMEINEj Aug Sep Oct Nov Dec

latitudealtitude

=MRMINIM.=14.76

IMMIEBIEBBMINIMINIMMISEEMBEEDIEMIUMIMINIRH (%)

29.2

81

30.4

76

31.424.6 26.8

IMMIIIIMMIMIN27.9 29.9

37.430.3

36.7 36.5 34.7 MIEN 29.229.0 27.9 MED 21.0 19.3

78 78303.4 253.4

11111117AMISINIMINIIIRMISSI272.6 280.3 241.9

69288.0

69MIENUMIENO

MIMI111.111111111111111sun

1988

11...11precipitation

windrun (km/day)(hour/day)

(mm/month)

291.8 337.9 376.3 422.48.6 8.0 8.3 9.4 10.1 9.0 5.4 6.4 6.6 9.5 9.7 9.50.0 0.0 0.0 39.0 0.0 0.0 MEE 61.4 MEN 0.0 0.0 0.0

130IIIIIIIIMIIIIII IIIIIIMIIIIIIIIIMIIII all 24.3station Hodeidah ( Airport ) Feb MIMI Apr M IIIIEMEMEIMIM EM Au Sep Oct DgNov Declatitude

MIMMI

station

111.11.111RH

14.76altitude 111.1.111311INEMBIIIIIIMINII(%)

28.7 28.8 29.8 31.6 34.3 35.6 37.0 37.0 MEN 34.7 MEN

63380.2

21.81.11115130.7

I=MIIMEE21.0 21.8 22.4 24.5 26.8 28.1 29.2 28.7 27.6 25.4

MIME 74 111111113=1112 74 =1E1 63 65 65 68

1.1.1.1.1111111.11sun1.1.111111.111.1.11precipitation111111111111111111.11ETO

1989 windrun (km/day)(hour/day)

(mm/month)(mm/month)

280.3 303.4 368.6 380.2 299.5 307.2 314.9 291.8 280.3 276.58.9 8.3 7.6 8.9 10.5 8.2 7.8 7.4 8.0 9.0 9.9 8.5

51.4 10.5 56.4 89.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

INIM 134 150 ME§ 187 184 207 195 192 111116111111121 136IMMINIMilliIMMIMMIIIINEMMIIIIM

0.5 ETO (mm/month)

Hodeidah ( Airport )

61 67 =El 87 94 92 103 97 96 85 87 68

24.9 M.I1 26.1 28.1 30.6 31.9 MIME 32.9 32.6 30.1 MOM 25.9

EOM Feb MIME APIIIMEEMMUMINIMEM Aug Sep Oct Nov DecMHO

19.8latitude

11111===1111111=01521.11111111

altitude IMIIIIMIEMEEM11111111111131MINEM14.76 laMONIMEMME

RH (%)

30.4

74

30.4

69

31.9 33.6 MEE 36.9 37.6 =Me 37.0 35.4 32.8MEE24.3 MIMI 27.0 28.1 28.7 28.6 IMES 24.4

66 IIMIREINIMIN111111 64 66 67 63 67 74

272.66.0

357.17.0

368.68.0IIIIIIIIIIINilli 314.9

9.0349.4

10.0395.5

10.0460.8

9.0

IMMIIMMIN 0.0 16.3 9.9 5.8 0.0 0.0 0.0 0.0 1.6 0.0 0.0 0.0IMMIIMMIIIIIIIIIII111111.1111...11 0.5 ETO (mm/month)

126 136 167 163 190 195 218 201 198m 167 138

63 68 83 81 95 97 109 101 99 98 83 69

IMIIIIMMIl l 25.9 27.0 28.1 29.4 MIENIIIIIIMINIEBEI 33.0 MIES 29.9 MEIN 26.6

Fig. 3 Hodeidah : Precipitation and evapotranspiration graphs 1983 - 1986

13

300

250

200

Hodeidah: Precipitation and ETO1983

300

250

onn

Hodeidah: Precipitation1984

and ETO

Immal111111111101111111111NI amommits MI MIMI MII MIMIMI Ill 1111111111111110111M11111romme mumm....0 II PA_

-.E

150

11.1111.1.ZMIMINIMIlaiLME11111111Imimmosmnimomniam2 .....l, oi

--E

E- 100

so

IMMEMEMIEIMEMEEMIIIIIMMIEVIEllEIMIIIII 111101111111EMENIMIIINVIMMENSINIffirMNIIII

Ewe 11111=111111161111IN,

150

E

E 100

IIP ...AI.LIM

MEW-

1111111111=11111111111'mil=

zooI'M En

IIIIIJM,IMIIII1101. .or

Jan Feb Mar Apr

1111111111114101111MWM ME

Mill50

MWIIMIIINIII MOO . . .

May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

m precipitation 0-- ETO 0 0.5 ETO ea precipitation (mm/month) 0 ETO (mm/month) o 0.5 ETO (mm/month)

Hodeidah:

3 0.1...250 in, mil

200 MN

Precipitation and ETO198 5

Hodeidah: Precipitation

300

1986

and ETO

E Nommomm.1..2.1111101MaillE101

2 Nimm.IIIMEMINIE al

200 MI El 111111111

,-2

? 15°

EE

-1°°

In El MIIIMMIIIIIMMII11111111111111EPI EIMMOME1111111111111111111111EENIIIIKEINUMWMEMIE

EREM11111 IIIMIMMIll

-tE 150

,111111maimilll

al1111111111111111111111EM

50 IIIMMEINEMIE

11111.11111111111111101111K4

WEEMIllIIIII1MMIIIII111111MIEM

-.44

Ill

---E

E100IOW lit IMEIMMIm- orminas

'MIMEO'S--6.- . MIMEMIII

May Jun JulAug Sep ¿et

,,I50

o IlME=MUM

OWEIEEE

_......,===1 MINov DecJan Feb Mar Apr Jan Feb Mar Apr May Jun Jul Aug Sep Oct

.

Nov Dec

0 precipitation (mm/month) o ETO (mm/month) 8 0.5 ETO (mm/month) 0 precipitation (mm/month) --o ETO (mmtmonth) ..C. 0.5 ETO (mm/month)

EE'-'l

250

2 150

50

Hodeidah : Precipitation and evapotranspiration graphs 1987 - 1990


n Feb Mar Apr May Jun Jul Aug Sep Oct Nov D c


300

Jan Feb Mar Apr ay Jun Ju Aug Sep Oct Nov Dec

14

200

g 150EE

100

50


111111111111101111M011111111111111111111

11111=111111.ftamad=11111111

11711101111111111111111111111111111MMONINIMI11111111111111Walmit MIMEJan Feb Mar Apr May Jun


ar AprJan Feb ay Jun ul Aug Sep Oc Nov Dec

1011111111111111111111111111111111111111111MIMO MIL111111111111111111111111111111=11MI MIMIIIIIIIIIMIIMIMIIIIIIMIIIIIIIIIIIIIIMIIIIMIIKIIMIMIIIIIMIIIIIIIIIIIIIIIIIMII 1110111111111111111111111111111111

-""ItsWatilliiiM11111IMIZIMIIIIMIl111111111111P="nomMILMMIIMESTWIIIIIMIWIlhi 11111111111M11115011111111111111111111111 111111111111111111K1111

MINE1111111111P110111111111111110,11

11111M.111111111111111111111111111111111111MEMIMINIM011111111111111.11111.0111111M1111111120010111111111111PwLM11111mmitlIIIIIN11111111118110.1111111111111111111111M01111wormilM11111111111111110111111111111111111E1

111.11111_,,marek__IrninillmM111111111111111111111111111ill1110M11111101=111M111111111111111111111111111111=11111111011111111111111111111111111111111

o Nimmumminsmomorm auruammum imam amWillirmalmummonlam slommiewmmommiOurmumanammiommicidurommammgemmiamimmlimmilla50 limmunimmmrsiimmiliamporimials

ul Aug Sep Oc Nov Dec

-m- precipitation (mm/month) -a- ETO (mm/month) -a-- 0.5 ETO (mm/month) -R4- precipitation (mm/month) 0 Fro (mm/month) -a- 0.5 ETO (mm/month)

-01 precipitation (mm/month) a ETO (mm/month) -a-- 0.5 ETO (mm/month)-ea-- precipitation (mm/month) ETO (mm/month) 0 0.5 ETO (mrn/month)

3

250

300

250

-.200_c

ZS"

E 150

E100

300

250

200

g 150

EE

100

between below 20°C (rarely) in winter ro over 40°C in summer. Rainfall is very inconsistentin time and space. The elltirC region is under the influence of the monsoon, which bringssurruner rain with cloudbursts, mainly in July and August. Rainfall during the winter season isvery rare.

The total amount of precipitation is usually less than 2(X) mm. The average annualair humidity is about 70%, but can be as much as 90% and more at night and dev,, is verycominon. Winds generally blow from south-west or north-west, sometimes at high speed,causing sand movement and deflation, especially on cultivated fields. Table 1 provides theclimatic data for Hodeidah airport. (1983-1990), which can be considered representative for thesurvey area.

Rainfall in the Tihatria

Yemen as a whole is characterized by very intense showers, but the hig.hest intensitiesare experienced in the Tihama. Within the Tihama itself, rainfall is very rare along the desert-like coast and increases both in frequency and intensity towards the interior.

The inhabitants of the Tihama have developed t1e cultivable land in suc.Th a way as toderive the grea.test possible benefit from this precipitation. In the upper area of the coastal zone-fields are designed to trap rainwater which can not infiltrate as fast as it falls, thus preventingit from running off downstream.

In the sandy part. of Tihama, the sand dunes are sos,vn after each heavy shower andinfiltration water, held within the sand, the dry surface of \VhiCh became impermeable, is

sufficient for rnillet to grown. If, by stroke of luck, two or three heav,/ showers occur soonafterward then the millet May ripen and provide a grain harvest. This happens about once every3 or 4 years. Otherwise the crop will still be useful as fodder.

1.8.2 Rainfall distribution

Figure 3 displays the variation in annual rainfall. It can be seen that time Hodeidaharea in fact exhibits one rainfall pattern. Along the coastal strip there is a desert c.limate withami annual rainfall of less than 50 mm falling in the form of 5 or 6 ShOWerS per year. Everyyear, On average there is one shower exceeding 20 mm. According to the available rc.Tords, aheavy shower of 89 mm capable of effectively irrigating the soil occurred only once in the \,,,ear1989. TI-mis zone CaIMOL be cultivated using rainwater alone. For this reason, this zone requirescomplementary irrigation by floodwater or from wells in order to make up for the deficiency andirregularity of the precipitation.

It should be added that the spring rains represent the maximum percentage as averagethroughout 8 years. In other words, there is almost certain to be a shower of at least 25 min inspring.

The Hodeidah airport station series which includes recorded values taken over a

period o-f 8 years (1983 - 1990), indicates that the low rainfall of the coastal strip remains validin the Hodeidah area. The length of the series is obviously too short for a precise appreciationof average rainfall at this measuring station, but it can well be seen that there is ami overall

15

consistency. Hence this rainfall pattern is identical in the whole of the study area. The meanmonthly rainfall has been plotted in figure 4.

To show more detail 1,vith respect to aridity, a classification proposed by UNESCO1979 can be used. lt is based on the ratio between average annual precipitation (P) and annualpotential evaporation (Eo) and in principle distinguishes five different classes

According to this classification, the study area falls in the arid class. For more detailssee figure 5.

1.8.3 Temperature

Average temperature are dominantly high as shown in table 2 (29.2-37.4C). Theannual range in temperature (i.e. the difference between the average temperatures of the summerand winter) is fairly constant, as it is only 7-9*C (see table 1) in the coastal zone in which Al-Hodeidah is situated. The proximity- to the sea and the moisture content of the air are thecontrolling factors. Average minimum temperatures vary between 20"C in December anclJanuary, and 37.4'C in July.

1.8.4 Evapotranspiration

The theoretical water balance established using the figures from Hodeidah airport(figure 4) uses 3 curves representing the monthly mean ra.infall in mm, the potential evapotrans-piration and a value equal to half the potential evapotranspiration (calculated by using thePenman method). It is conventionally assumed that plants are in vegetative activity when rainfallequals or exceeds .ETp12. From this graph it may be seen that the rainfall is alwaysconsiderably less than half the potential evapotranspiration. This situation is characteristic ofa dry tropical climate.

1.8.6 Other dinctly observed meteorolo2ical parameters

Important meteorological variables other than precipitation and temperature, observedat the meteorological station at Al-Hodeidah airport include the following (average monthly dataand average annual totals are listed in table 2):

Sunshine durationRelative humidityWind velocity.

Comparison between records and impressions from field visits indicate that time

accuracy ancl reliability of these meteorological data may be questionable for part of the records.

16

Flyper-arid P/Eo <0.03Arid 0.03< PIE° <0.25Semi--arid 0.25< P/Eo <0.50Sub-humid 0.50 <P/Eo <0.75'Humid P/Eo >0.75

Table 2 Average climatic data for Hodeidah (8 years)

17

station Hodeidah Air ort Jan Feb Mar A r =WM Au Oct Nov Declatitude 14.76 Tmax °C 29.2 29.7 Mile 33.4 35.0 36.4 37.4 36.8 36.9 34.8 32.1 31 4altitude MI.111111MBIMIIIIM 20.0 111.111111111Ela 25.5 27.4 28.7 29.2 28.9 27.6 25.0 21.4 206

RH % 79 78 79 79 78 75 73 =al 70 73 73 78ear av . 83-90 guarrialaMIIIMI 378.3 380.2 MIMI 388.3 313.0 L1 293.3 280.8 307.7 360.0 350.4

1.1.11M1 sun hour/da 8.1 8.2 8.2 9.0 9.3 6.9 IIIIMPEIIMEI 9.6 9.8 8.9reci itation mm/month =UR 10.3 24.3 IIMINEI 3.4 7.7 3.6 0.0 0.0 0.71.11111.1.1311mm mon =NEI 128 146 165 179 172 180 178 177 169 147 121-

I. I mm/mont MI 57 64 83 90 86 90 89 88 84 74 611.11111111111=SMIIMIN 24-6 29.4 31.2 32.6111.11131Mala 32.2 29.9 26.7 25.7

Fig. 4

300280260240220

,--.200180

° 160E--- 140E

120E10080604020

O

od oah: Precipitation andaverage 1983-1990

t;:Iwilm=;5:S5

ar Apr May Jun Jul Aug Sep Oct Nov Dec

precipitation ETO 0 0.5 ETO

TO

Jan Feb

FIG. 5 CLIMATIC ZONES IN YEMEN

S."<"1111

aF,

oSaha'a

. .

OhIrnar

"

. .

19

uk313

100 200 km

Source: The Water Resource of' Yemen ( 19)5) Report WRAY-35

Al Ghaydahj-

[J h7Per-add P/E0 <0.03

r.i arid 0.03 <P/F.0 <0.25

semi-arid 0.25 <P/E0 <0.50subtiumid 0.50 <P/E0 <0.75

Careful quality assessment is certainly needed, but this is beyond the scope of this report.Relative humidity data are perhaps the most suspect data in this respect, because calibration andprocessing is more difficult for these than for other data types. Although in general datarecorded at a station are not necessarily representa.tive for its wider surroundings, this is not checase in the Hodeiclali area where relief is rather subdued.

Clear skies are the norm in the Tihania during most of the year. This is reflected inthe records of sunshine duration, which on average vary between 7 and 9 hours per day, corres-ponding to 50 to 75 % of the theoretical maximum. Absence of stmshine during daytime is notonly caused by clouds, but mountains may also shorten sunshine, duration because of the shadowsthey produce after sunrise and before sunset, although this does not apply to the survey area.

The relative humidity v-aries between 70 and 80 % for the coastal plain.

Average wind speed is generally strong along the coast. The annual average valuesrange between 307 and 388 km/da. It is believed that part of the difference in che survey areahas to be attributed to effects from sand dunes (it has not been verified whether the wind speedat Hodeidah airport has bc.!en measured at the standard height of 2 m above surface). When are

20

Chapter 2 METHODS

2.1 PHOTOINTERPRETATION

Aerial photographs, sc,ale 1:60,000 (1973) and topographic maps (1:50,000) were usedduring the survey. I3y examining aerial photographs, it was possible to establish a preliminarydefinition of landform, broad categories of vegetation, cultivated areas and to prepare apreliminary outline of the physiographic units based on common characteristics.

During fieldwork a fil al working legend was developed, as the bou ndaries of diemapping units were checked and progressively refilled by API. The soil map, land use map.vegetation map and physiographic map were completed after final interpretation of the aerialphotographs and compilation of mapping units on 1:50,000 topographic base map. Severalreports on the soils and other physical features related to agricultural development of the Tihamacoastal plain were consulted.

FIELDWORK

As a preliminary step in establishing a soil working legend, a rapid reconnaissancesurvey was made together with some auger checking to identify the main soil types. Based onthis some areas were then selected from aerial photographs, and further ground observationswere carried out at semi-detailed level to establish the pattern of soil distribution. The main soiltypes were characterized by profile pits. The described profiles were subsequently used locharacterize each of the mapping units, with one or more soil pits being opened depending onthe complexity of the soil pattern .

The actual fieldwork was completed after one and half month, excluding the time spenton a complementary study of soil characteristics. Profiles were examined, where, possible, toa depth of 120 to 150 cm. Each observation includes a description of the site (parent material,landform, vegetation, land use), general information o» the soil (drainage, depth. stoniness,erosion. human interference) and soil morphology. Water samples were collected from waterpumped for irrigation throughout the area for analysis to determine their suitability class forirrigation.

Vegetation and land use studies were based on the preliminary photo interpretation andlater on supported by field investigations. Previous studies were consulted and verified by thefield identification.

LABORATORY ANALYSIS METHODS

A11 samples collected in the field were analyzed at the Dhamar laboratory of the'ntly established Renewable Natural Resources Research Centre, where the analyses were

d out under supervision of Dr. A, E. Fad], the soil chemist of FAO's EnvironmentalAssessment for Rural Latid Use Planning proleet. The methods used are listed in3.

21

The Tihama is mainly a region of deposition, starting with gravels and stones near thefoothills and ending with fine sands and silts near the coast. As stated before, three maindeposits can be identified in the coastal plain

Alluvial (wadi Siham)AeolianFluvio-Marine

The soils derived from these deposits are generally little- developed, due to theextremely dry climate and the short cievc.qopment period for the recent deposits. With theexception of the soils of the old wadi terraces, these soil are deep and somewhat compacted witha pH of between 8 and 9. They contain little organic matter and nitrogen and low to very lowamounts of phosphorus, but plenty of potassium. All the soils are moderately to stronglycalcareous, but the calcium carbonate content does generally not exceed 10%. They aregenerally well drained, but locally layers of fine elements (loam and clay) slow downinfiltration. The material transported by wadi Siham, which covers part of the study area, variesconsiderably. In the alluvial plain along wadi Siham, it is clear from time deeply incised valleysof the wadi and its tributaries that the substratum is stony in nature. Sometimes even up to thesurface the loamy cover is absent.

In this alluvial plain, the deposits are much finer in texture (loam) than in theaccumulation plain which stretches to time edge of the Red Sea. The aeolian sand deposits formvast expanses on the north side of the alluvial plain. They have formed a round longitudinal andbarchan dune network. These consolidated dunes date from an arid villafranchian period(Sogreah 1981). It became separated by the alluvial deposits of wadi Siham during the pluvialperiod at the beginning of the Quaternary.

These dunes are elongated sand hills to the north of study area, the hills often being14.5 km long. 1"urther on these bars become incoherent and form a vast clune field, partiallyfixed between Al-Baydah and km 16. The large number of these shifting dunes has restrictedagricultural development. In the area of marine deposits, saline soils with a noticeable contentof chlorides and sulphates of sodium dominate. They only bear a sparse vegetation cover, whenthey are topped by thin sand layers. On fluviatile and aeolian deposits 1,ve find a predominanceof sandy and silty soils with a very low humus content (0.5-1.0 %) and almost no differentiationinto strata. Dunes and mobile sands play important role for the vegetation though they are nottrue soils. So we may distinguish three major types of natural environments in the study area.distributed in a fairly regular pattern (see cross sections in appendix 4). This subdivision of thestudy area forms the basis of the legend of the 1:50,000 soil map, given at the end of this report(appendix 4).

The marine salt flats near the sea (alluvio-marine),Aeolian sand deposits (dune land arca)

. Alluvial plain within the wadi. systems.

Chapter 3 SOILS

3.1 ORIGIN OF THE SOIL

22

3.2 SOIL PROFILE CHARACTERISTIC AND PROCESSES

The alluvial deposits, derived principally from wadi Siham, frequently show littleindication of pedogenetic development. Where profile modification is evident, it is expressedas an A horizon overlying a Cambie B horizon. The aeolian deposits are common on the northand north-ea.st of Hodeidah where there are elongated sand hills which occupy much of the land.Profile observations in the aeolian deposits were done in between the dunes. An Ochric Ahorizon occurs over a Cambie B horizon and in some part over the nodules of calcium carbonateof the substratum underlying the dunes. It should be noted that in a dry state hardened layersare very common in this area due to the presence of calciuin carbonate and silt deposits which.upon drying, can become very compact and hard. These layers continue to a depth of 60-80 cm.

The alluvio-marine deposits are found in the northern and southern part of study areawhere the profiles show the presence of a Calce B horizon and the shells throughout theprofiles. In general, more recent sedimentation is reflected in increasing hetenageneity andstratification.

3.2.1 Soil texture and stratification

The soils of the alluvial &posits along wadi Jahef (wadi Siham tributary) starting fromAl-Za'afaran extending to Quza'at-Aldupal towards Al-Mashagenah in the west, show relativelylittle variation in texture. The silt + clay fraction is generally higher than 60% and the sandfraction is predominantly very fine and fine (see analytical data in Appendix 1). The maintextural classes are loam, silt loam, clay loam and silty clay loani. Sedimentary stratificationis not a prominent feature in the majority of soils.

Irrigation practices based on flood control and the diversion of flood waters havecontributed to texture properties over the years. In regularly flood irrigated land, particularlytowards the head of the valley terraces south of wadi Jahef (mapping unit W i 12) and east of Al-Dupal village, the soils are fine textured with a silt -F clay content nc.wmally exceeding 90 %(profile HUE012). The soils are derived largely from sediments carried by spate flows. Furtherthe soils north of wadi Jahef, starting from Al-Guraibah towirds Al-Sharff villages and exten-ding to the Hodeidah-Sana'a main road, are predominantly medium to coarse textured (profilesHUE020. 11U[021, H1JE022. FILIE024). At a more detailed level, the finest textured soils areoften restricted to the lowest-lying positions within individual fields. Apart .from the finestsediments settling, out in these depressed tireas, the breaching of builds al these low points,allowing irrigation water to pass to adjacent fields, is followed by the removal of surface soi]during their repair resulting in the exposure of a finer .textured subsoil. Other minor texturalvariations are occasionally found adjacent to irrigation channels where coarse material (sand orloamy sand) has accumulated as a thin surface deposit.

East of Quza'at Al-Dupal \Tillages (unit W112 of alluvial terraces) borders the courseof the incised wadi bed (profile HUE025, wad Jahef terraces). Intermitwnt flooding anddeposition, which at present affects only the lowest terrace level, have produced stratified soilprofiles usually marked by contrasting layers of coarse and medium textures (profile Elliii024,Al-Graibah village). This profile, is characteristic of soils which can be described as levee soils.These medium textured profiles are frequently inter-stratified with gravel layers (H (JE024). The

23

bed of wadi Jahef is composed of subrounded gravel, stones or boulders but going westwardsthere is an increasing proportion of medium and coarse sand. The alluvial plain, bordered tothe north and south by aeolian deposits of fine sand, has been subject, during historical times,to natural deposition. The distribution of sediments and their variability are related to pastchanges in the course of wadi Siham.

Soil showing very weak textural contrast or stratification compared with thoseelsewhere on the alluvial plain occur within three areas, straddled by the Hodeidah-Sana'ahighway south of Al-Oga village, north of Al-Sharaf village and Quza'at Ai-Dupal towards Al-Sela'a village. The uniform sandv loam profiles, as represented by profiles HLVD052, HUI)053,HUD051, HUE020, HUE022, HUE026, HUD055, have a distinctive particle size distributionwith low ( < 30%) silt contents. Very similar material occurs at depth in several profiles (e.g.HUE023, HUX025) and is probably the oldest alluvium exposed in wadi Siham.

The plains are affected throughout the year by the encroachment and redistribution ofaeolian sand. Apart from the period between April/May and August/September, when theprevailing wind is from the N-NW, the principal direction of movement is from S-SW. Over-blown deposits of loose fine sand, loamy fine sand or occasionally fine sandy loam are prevalentimmediately east of the Hodeidah-Jayzan highway and south and south east of the Hodeidah-Sana'a highway (HUD052, HUD051, U1)050), but are progressively less common towards thesecond water pumping station (Al-Baidah). Here high dunes stabilized by some vegetationconstitute a microrelief of aeolian hummocks scattered over the alluvio-marine deposits in thesouth towards the sea, where the soils have developed within alluvio-marine sediments, probablyoriginally deposited in the coastal salt flat. Texture is predominantly medium and fine(HUE029, HUE027), although an extensive area has been modified by sand encroachment frornshore line deposits resulting in a superficial cover of variable thickness partially stabilized byOdyssea species.

3.2.9 Depth

The effective depth of most soils exceeds 250 cm as indicated by cuts and by augerborings within the survey area. Deposits of gravel or stones probably underlie the alluvialdeposits, frequently oceurrin2. within 2 meters of the surface at Al-Guraiba village (HU[024).The majority of soils fringing the upper reaches of wadi jahef have a nodular or massivecarbonate horizon within 1 meter of the surface near Al Mashaqenah (profile HUE026).Nodular carbonate concretions occur at depth in other soils, usually within a uniform matrix offine sandy loam (profiles HUD050, HUD051), located east of Jayzan road, and north and north-west of wadi Jailer (profile HUF,028) in the alluvial plain.

3.2.3 Colour

Pedogenic processes which modify soil colour are weakly expressed in \,vadi Jahaf asa result of the arid climate and the recent deposition of much of the alluvial sediment. Colourgenerally reflects that of the parent material in the absence of a well developed B horizon andany significant accumulation of organic matter. Light yellm,vish brol,vn (Munsell notation 10YR6/4, dry) to dark yellowish brown (10YR 4/4, moist) colours are usual throughout the profilewithout any marked variation with change in the texture.

Free carbonate is evident in the finer textured layers of alluvial plain soils as sxhitepseudomycelia occurring below the surface horizon, but this contributes to the matrix coloursof the soil only in cases where it has formed a continuous impregnation of the soil mass, usuallyassociated with nodules or weak cementation, giving a very pale brown (10YR 7/3, dry) toyellowish brown (10YR 5/4, moist) colour. A dark brown (10YR 4/3 to I0YR 3/3) horizon isoccasionally found overlying a zone of carbonate accumulation.

Concentrations of iron oxides, principally magnetite derived from weathered basicigneous rocks of the catchment, probably cause the darkening, of these horizons and are alsofound as scattered deposits of black volcanic beach sand along the coast. Soil mottling isuncommon, being restricted to occasionally rusty inter-lamella mottling in fine textured horizonswith slightly impeded vertical permeability, in stratified soils and to glev and oxidation mottlesin soils with a high water table near the coast.

3.3 TAXONOMIC SOIL CLASSEFICATION OF THE STUDY AREA

The soils are classified according to the Soil Taxonomy and the Legend of the FAO-Unesco Soil Map of the World (1988). However, the available soil analytical data areinsufficient to proper classify the soils clown to Soil Taxonomy family level. The very fine sandfraction is essential to determine the textural class correctly, and also mineralog,ical data havenot been determined. Therefore, the family level classifications given in the soil profiledescriptions (see Appendix 1) should be considered provisional and is not included in tire soillegend.

To classify soils according to Soil Taxonomy, estimates of the climate regime arenecessary. The 'available climatic data indicate that the soil moisture regime is aridic and thesoil temperature regime is isohyperthermic, with a mean annual soil temperature >28°C andthe difference of mean summer and winter soil temperature being more than 5°C (Rhebergenand van Waveren. 1990).

The following Soil Taxonomy subgroups and equivalent FAO soil units occur in thesurvey area

Typic TorripsammentTypic TorrifluventTyp ic TorriorthentTypic HaplargidTypic Haplocalcid

3.3.1 Diagnostic horizons

Calcaric Arenoso]Calcaric FluvisolCalcaric RegosolHaplic LuvisolCalc;.-tric Calcisol

Cambic horizon : recognized on basis of structural development rather than on colour. In thestratified alluvial deposits colour is a geogenetic phenornenon rather thanpedogenetic.

Cakic horizon ìn the survey area calcic 110riZOJIS are found as light coloured bands withnodules andior soft powdery lime occurrences.

The most common soil orders in the study area are the :EntisoIs and Arid's°Is. Thereis some variation, primarily in a north-south relationship, in soil characteristics such as textureand carbonate content. In the legend soils are named by the predominant soil order. Each ofthese predominant soil orders is described below.

3.3.2 Finis°Is

Most soil in the study area are either subject to constant erosion and or depositionprocesses by wind and water or are the product of recent deposition with the result that stronglyexpressed profile development is rare. The dominant soil order is therefore the Ends°ls. whichgenerally speaking are young undeveloped soils. Ends°Is are strongly influenced by alluvial orloessal calcareous silt parent materials, but on the plains where sand has accumulated in dunes,Psamments are common.

Orihents

Fluvents

Psamments

3.3.3 Aridisols

In arid regions characterized by a stable surface, calcic horizons have developed sothe soils are classified as calcids. Cambie horizon were observed in som soils and these have,been classified as cambids.

3.3.4 Soil moisture regime

The iinportance of the soil moisture regime, which ranges from aridic to udic, areapparent to anyone with any practical agricultural experience in Yemen. The predominant soilmoisture regime is usually given in the soil family name. The moisture regime are defined interms of the groundwater level and in terms of the presence or absence of water held at a tension< 15 bars in the moisture control section by periods of the year. tt is assumed in the definitionthat the soil supports whatever vegetation it is capable of supporting. In other words, it can becrops, grasses, or native vc_Tetation. It is not being fallowed to increase the amount of storedmoisture, nor is it being irrigated by man, as such cultural practices affect the soil moisturecondition.

Dominant in the most arid areas where organic matter decreases in auniform manner with depth.The most common soils of the alluvial terraces along Wadi Siham, but alsoin the south the study area where they occur together with the mostextensive calciorthids.Soils formed in sancly material. In aeolian material (duneland) soilformation is often minimal due to the absence of vegetation and unstablenature of the sand.

26

Ochric horizon generally weakly developed surface horizons which have low organic carboncontents, light colours, and often weak. structures. It should be noted thataccording to the definition the finely stratified materials as found in basinirrigation areas do not qualify as Ochric horizon (such topsoil layers, not yetaffected by soil-forming processes, lack the properties of any diagnostichorizon and are therefore considered C material).

in the survey area, the prevailing soil moisture regime is nick or torno (these termsare used for the same moisture regime but in different categories of the taxonomy). Accordingro the Soil Taxonomy (1975), the aridic (torrie) moisture regime is characterised as follows

Dry in all parts more than half the time (cumulative) that the soil temperature at adepth of 50 cm is above 5°C and,Never moist in some or all parts for as long as 90 consecutive clays \,vhen the soiltemperature at a depth of 50 cm is above 8°C.

Soils that have an aridic or torric moisture regime are normally in arid climates. A'few are in semi-arid climates and either have physical properties that keep them dry, such ascrusty surface that virtually precludes infiltration of water. There is little or no leaching in thismoisture regime, and soluble salts accumulate in the soil if there is source of them.

3.3.5 Soil tempercture regime

The importance of the soil temperature regime designation may not be as immediatelyevident as tha.t of the soil moisture designation. This does not in art ' way, however, diminishits importance for agricultural planning. If the name of a soil temperature regime has the prefix"iso", the mean summer and winter soil temperature for Rine. July and August- and forDecember, january, and February differ by less than 5°C at a depth of 50 cm.

The following description of the isohyperthermic soil temperature regime, whichrepresent the study area, is taken verbatim from Soil Taxonomy 1975.

The mean annual soil temperature regime is 22°C or higher, and the differencebetween the mean winter and summer temperatures is less than or equal to 5°C

3.4, THE SOIL MAP

3.4.1 The soil legend

The legend to the soil map is given in tabular form. A more extensive description ofeach soil unit is given in the next section. The structure of the soil leg.end is hierarchical andconsists of four levels. The soil information at the lowest level is comparable to that of the SoilTaxonomy family level. The four levels are:

I. Major landscape 3. Relief2. Lithology 4. Landform

The soil units are identified by a four dig.it code following the same hierarchicalsystem. The first character gives the major landscape. In this case C stands for coastal plainand W represents the Alluvial plain. The next three numbers give the lithology, relief andlandform. The type of mapping units consists of undifferentiated groups. complexes, andconsociations of two to four soil units, which can not be mapped separately at 1:50.000 scale.

27

The soil map legend was clefined on the basis of soil genesis concepts and field surveyprinciples discussed prev-iously in this chapter, and the Soil Taxonomy (USDA-SCS, 1975) wasused for soil classification. It was decided to divide the legend into nine parts based on thelandscape, lithology, relief, landform, geomorphology and the predominant feature of each ofthe individual map units. Table 4 shows .the legend with the main characteristic's of eachmapping unit.

Individual soil profiles are classified to the family level (Appendix 1.). Twelvemapping units were identified based on their soil characteristics and physiographic characteristicsof the dominant features in each unit.

The map at scale 1:50,000 was used to determine the approximate areas of thedifferent mapping units classified at sub-group leve]. The calculation was made using aplanimeter, and the results are shown in table 3. The total survey area amounts to about 15,195ha. The percentage of total area of each mapping unit is given in the legend. The profilesrepresenting the various mapping units are indicated in the legend by their profile codes. Fulldescription of these profiles along with laboratory data are given in Appendix 1.

Table 3 Area measurement of soil mapping units.

Two cross sections (AB and CD), representing the various landscape features areshown in the soil map. The first one starts from a point in the sea west of the layzan road toAl-Oga village in the east. The second one shows the different features from a point in the seawest of Al-Manzar village to Al-Za'afaran village in the east. For more details refer to the soilmap in Appendix 4.

28

Soil mappingunits

Area (ha)

1 Ci11 2622.5

1 C122 1017.5

3 CI33 3375.0

4 C144 537.5

5 C211 657.5

6 C212 680.0

7 C221 760.0

8 C222 1002.5

9 C223 1412.5

10 W111 1447.5

11 W112 1440.0

12 wad i-bed 242.0

Total 15,194.5

Chapter 4 LAND SUITABILITY CLASSIFICATION

4.1 GENERAL

Land suitability is the fitness of a given type of land for a defined use. The land maybe considered in its present condition or after improvements. The process of land suitabilityclassificaticm is the appraisal and grouping of specific areas of land in terms of their suitabilityfor defined uses.

There may be certain parts of the area considered, for which particular kinds of useare not relevant, e.g. irrigated agriculture beyond the limit of water availability. In thesecircumstances, suitability need not be assessed. Such parts are shown on maps or tables by thesymbol NR: Not Relevant.

4.1.1 STRUCTURE OF THE SUITABILITY CLASSIFICATION

The framework of suitability classification has a uniform structure, i.e. it recognizessimilar suitability categories in all kinds of interpretative classification (see below). Thus, eachcategory retains its basic meaning within the context of the different classifications and asapplied to different kinds of land use. Four categories of decreasing generalization arerecognized

Land Suitability Order: reflecting kinds of suitability.Land Suitability Class: reflecting degrees of suitability within orders.Land Suitability Subclass: reflecting kinds of limitation, or main kinds of improve-ment measures required, within classes.Land Suitability Units: reflecting minor differences in required management withinsubclasses

4.1.1.1 Land suitability orders

Land suitability orders indicate whether land is assessed as suitable or not suitable forthe use under consideration. There are two orders, represented by the symbols S and Nrespectively.

Order S (Suitable): Land on which sustained use of the kind under consideration isexpected to yield benefits which justify the inputs, without unacceptable risk of damage tonatural resources.

Order N (Non--suitable): Land which has qualities that appear to preclude sustained useof the kind under consideration. Land may be classed as Not Suitable for a given use for anumber of reasons. It may be that the proposed use is technically impracticable, such as theirrigation of rocky steep land, or that it would cause severe environmental degradation, such asthe cultivation on steep slopes. Frequently, however, the reason is economic: that the value ofthe expected benefits does not justify the expected costs of the inputs that would be required.

30

4. 1. 1.2 Land suitability classes

Land suitability classes reflect- degrees of suitability. The classes are numberedconsecutively, by arabic numbers, in sequence of decreasing degrees of suitability within theorder. Within order S the number of classes is not specified. There might, for example, beonly two, SI and S2. However, the lumber of classes recognized should be kept to theminimum necessary to meet interpretative aims. In general, five classes should probably be themost ever used. 11 three classes are recognized, as can often be recommended. the followingnames and definitions may be appropriate in a qualitative classification:

Si Highly suitable: Lancl having no significant limitations to sustained application of agiven use, or only minor limitations that will not significantly reduce productivity orbenefits and will not raise inputs above an acceptable level.

52 Moderately suitable: Land having limitations which in aggregate are moderately se.verefor sustained application of a given use; the limitation will reduce productivity orbenefits and increase required inputs to the extent that the overall advantage to begained from the use, although still attractive, will be appreciably inferior to thatexpected on class SI land.

S3 Marginally suitable: Land having limitations which in aggregate are severe forsustained application of a given use and will so reduce productivity or benefits, orincrease required inputs, that this expenditure will be only marginally justified.

In a quantitative classification, both inputs and benefits must be expressed in commonmeasurable terms, normally economic. In different circumstances different variables may expressmost clearly the degree of suitability, e.g. the range of expected net income per unit area or perstandard management unit, or the net return per unit or irrigation water applied to different typesof land or a given use. Where additional refinement is necessary it is recommended that thisshould be achieved by adding classes, e.g. S4, and not by subdividing classes, since the latterprocedure would contradict the principle that degrees of suitability are represented by only onelevel of the classification structure, that of the suitability class. This necessarily changes themeanings of class numbers, e.g. if four classes were employed for classifying land with respectto arable use and only three with respect. to 'forestry, Marginally Suitable could refer to S4 intire former case but S3 in the latter.

An alternative practice has been adopted in some countries. In order to give a constantnumbering to the lowest suitable class, classes have been subdivided as, e.g. S2.1, S2.2. Thispractice is permitted within the Framework, although for the reason given in the precedingparagraph it is not recommended. Suitability class SI, Highly Suitable, may sometimes notappear on a map of a limited area, but could still be included in the classification if such landis known or believed to occur in other areas relevant to the study.

Differences in degrees of suitability are determined mainly by the relationship betweenbenefits and inputs. The benefits may consist of goods, e.g. crops, livestock products or timber,or services, e.g. recreational facilities. The inputs needed to obtain such benefits comprise suchthings as capital investment, labour, fertilizers and power. Thus an area of latid ni ight beclassed as Highly Suitable for rainfed agriculture, because ti-re value of crops produced

31

substantially exceeds the costs of farming, but only Marginally Suitable for forestry, on groundsthat the value of only slightly exceeds the costs of obtaining it.

It should be expected that boundaries between suitability classes will need renewal andrevision with time in the light of technical development and economic and social change. Withinthe order Non-Suitable, there are normally two classes:

Ni Currently Not Suitable: Land having limitations 1,vhich may be surmountable in timebut which can not be corrected with existing knowledge and/or at currently acceptablecosts; the limitation are so severe as to preclude successful sustained use the [and inthe given manner.

N2 Permanently Not Suitable: Lancl ha.,'ing limitations which appear so severe as topreclude any possibilities of successful sustained use of the land in the giv-en manner.

Quantitative definition of these classes is normally unnecessary, since by definitionboth are uneconomic for the given use. The upper limit of class NI is already defined by thelower limit of the least suitable class in Order S. The boundary of class N2, permanently NotSuitable, is normally physical and permanent. In contrast, the boundary between the two orders,Suitable and Not Suitable is likely to be variable over time through changes in the economic andsocial context.

4.1.1.3 Land suitability subclasses

Land suitability Subclasses reflect kinds of limitation, e.g. moisture deficiency, erosionhazard, etc. Subclasses are indicated by tower-case letters with a mnemonic significance, e.g.S2m, S2e, S3me. There are no subclasses in class SI. The number of subclasses recognized andthe limitations chosen to distinguish them will differ in classifications for different purposes.There are two guidelines:

The number of subclasses should be kept to the minimum necessary to satisfactorilydistinguish lands within a class likely to differ significantly in their managementrequirements or potential for improvement due to differing limitations.

As few limitations as possible should be used in the symbol for any subclass. One,rarely two, letters should normally suffice. The dominant symbol (i.e. that whichdetermines the class) should be used alone if possible. If two limitations are equallysevere, both may be given.

Land within class NI may be divided into suitability subclasses according to kinds oflimitation, e.g. N-Em, Nlme, Min, although this is not essential. Land in class N2 will not beplaced under management for the use concerned and should therefore not be subdivided.

4. 1.2 Summary:

The structure of the suitability classification, together with the symbols used, is

summarized in table 5. Depending on the purpose, scale and intensity of the study, either the

32

full range of suitability orders, classes, subclasses and units may be distinguished, or theclassification may be restricted to the higher two or three categories.

table 5. Example of structured land suitability classification.

The land resources characterized in this study have been assessed for the following

irrigated agriculture in general- cereals, vegetables and tree species under irrigation- woodland, under rainfed conditions, for four tree species

The classification criteria for irrigation in general are discussed below, while those forparticular crops and tree species are given in tables. The ensuing suitability classifications arealso given in tabular 'form.

uses:

4.2.1 Soil texture

The particle size range or texture is an important factor, since it has a direct effect onnumerous soil properties (structure, permeability, a.eration.etc.).

The texture has been assessed as follows, in order of increasing particles size:

On referring to the texture triangle it was observed that the textures are mostly locatedwithin the coarse loamy and sand,; family textural classes, and that there is therefore littlediStifieti011 between the different texture classes. For this reason, there MUS1 be overlapping inthe particle size range defining each class of use.

33

ORDER CLASS SUBCLASS UNIT

S - Suitable Si ..... -

S2 S2e

S2mS2emetc.

S7e-1S2e-2

etc.

S3 S3t

N - Non suitable Ni N'I mN1 d

---

N2 --- ---

- Clay loam (CL) SI - Loamy sand (LS) S3Loam (L) S I Sand (S) S4

- Sandy loam (SI..) S? - Gravel and stones (X) N

meaning of limitations e erosion t texture ni soil moisture d drainage

4.1 CLASSIFICATION CRITERIA

There are some areas, in the downstream part of the central alluvial plain, where thesoil texture is very heterogeneous, as a result of mixed alluv-ial and aeolian deposits. These areaare characterized by alternating loatn, sandy loam, loamy sand, arid sand. A soil texture of thiskind is classified as class 3.

4.2.2 Soil depth

Soil depth can be a Ihniting factor of considerable importance in the case of thesuitability of soils for gravity irrigation. Roots must be able to penetrate as great a depth aspossible to be able to mak.e use of the water stored in the soil profile.

Furthermore, the soil should be able to store the large quantities of water suppliedwhen flood water is spread across fields. The depth scale adopted corresponds to that used forthe suitability classification of soils.

A soil more than 100 cm deep is classified as class i- A soil between 60 cm and 100 cm deep is classified as class 2.

4.2.3 Salinity

The electrical conductivity measurements of the soil water extract from the saturatedpaste were carried out in the laboratory. The salinity scale applied was the universally usedscale of the Handbook of the US Salinty Laboratory. For the salinity assessment this scale isapplied to themost saline soil horizon.

Thus, if the salinity were the only factor, the classification would be as follows

If the EC at 25°C of the paste extract is less than 0.5 dS/m, the soils falls into class

If the EC at 25°C of the paste extract is between 0.5 and 0.75 dSlm the soil falls intoclass 2If the EC at 25°C of the paste extract is between 0.75 and 1.5 dS/m the soil falls intoclass 3.

Problerns raised by salinity are of considerable importance in the central alluvial plain,in areas where pumping of groundwater has developed over the last dozen years. Thegroundwater pumped is often saline, and the volumes of irrigation leaching water are inadequateto ensure sa.tisfactory leaching of the soil, resulting in sodium accumulation.

4.2.4 Alkalinity

The soil where alkalinity is a problem are generally those where the salinity is fairlyhigh. Alkalinity gives rise to a high pH, reaching and sometimes exceeding 9. The alkalinityscale used relies on the exchangeable sodium percentage. Limiting values retained are 10 and15 % If alkalinity were considered to be only limiting factor, the classification would be as.follows

34

ESP less than 10 % : class 2-- ESP between 10 and 15 % :class 3

ESP greater than 15 % : class 4

However soils with an alkaline phase, on the other hand, are more wide spread, inparticular in the areas where pumped groundwater is used for irrigation.

4.2.5 Topography

The topography is a limiting factor throughout the study area. One of the reasons 'rorthis is that numerous mounds and dikes, sometimes over 2 m high, have been built to facilitatespreading and retaining floodwater in the alluvial plain and using rainwater and runoff in wadiSiham plains. These structures form a micro-relief which require further investigation if a large-scale irrigation project would be developed in these areas. Furthermore, in the downstream partof the alluvial plain, between Quza'at Al-Dopal and Al-Manzar villages in particular, there area series of dunes and hummocks, fixed by vegetation, which also constitute an obstacle todevelopment for irrigation, in addition to the textural constraint itnposed by the sand itself. In

the duneland area the topography is undulating as exhibited by the occurrence of sandhills, someof them over 5 in high due to active shifting sands. These structures makes development ofthese areas very difficult.

4.3 CLASSIFICATION TABLES

Table 6 shows the general suitability of the mapping units for irrigated agriculture,based on the criteria indicated in the previous section.

Table 6 Land suitability for irrigated agriculture

Tables 7 and 8 show respectively the requirements .for four iMpOrtatli forestry species,and the suitability of the mapping units for each of these species. Tables 9 and 10 list therequirements and mapping- unit suitabilities for irrigated crops and tree species respectively. Theinformation for these tables carne from the FAO Ecocrop database and El-Latifi (1995).

35

'lapping units Classification Suitability Area (ha) c7e)

W Ill SI good 2887.5 19

C113 S2 moderate 3375 2).1

C144C211C212 S3 poor 5050 33.3C221C222C223

C1(1C 112

N I Temporarilyunsuitable

3640 24

wadi bed N2 unsuitable 242 1.6

Total 15195 '100

'fable 7 Climate-, soil and water requirements for some selected woodland species under miffed conditions

Table 8 Land suitability classes for selected woodland species in the study area

36

Requirements

Tree type

Climate Soil NATat er

needTemp. & Humidity Rainfall Elevation pH Texture Salt tolerance

C'onocarpusLancifblius

high 50-400 nunlyr 0-1000 high sand,' to clayey moderate moderate

Azadirachra indica high 150-700mmiyear

0-1000 moderate ro high sandy to clayey slight moderate

Prosopis juiij7ora high 50-700 nun/yr 0-1500 high sandy high relativelysmall

Parkinsoniaaculeata

high 200- 1000mmiyear

0-1500 hig,h sandy, loamy high relativelysmall

Type of treeSoil unit

Conocarpus lancifolius Azadirachta indica Prosopis jidiflora Parkinsonia aculeata

NV I I I

W112 S2 S3 S? S3

C113 S2 S3 S2 S3

C I 14

C21IC2I2C22ICI??C223

S3 S2 S3 S2

CIllC112 SI S2 SI S2

wadi bed S3 N S3

Table 9 Clima,e, soil and water requirements for arable crops, vegetation and tree species under irr.gation

37

Requirements

Crop

Climate Soil Watertemp. raidall elevation humidity pH Texture IF,C

Cereals (sorehunL mil-let, etc.)

high 50-400min/year

0-1000 low tomoderate

mo&rate sandy toclayey

moderate moderate quail-tides

Vegetables (tontatoes,potatoes. water tuelou,sweet melon, beans,Okra, cte.)

moderate 50-400min/year

0-1000 low tomoderate

moderate sandy toclayey

moderate moderate to highquantities

Date palio high 100-400nu-it/year

0-1500 high high sandy roclayey

high relatively smallquantities

flyphaolc theboica high 50-700mill/year

0-1500 hioll hifli sandy toclayey


Teimarix iiilotica high 50-400nuniyear

0-1500 high hiyli,, sandy toclayey


Acacia tortilis high 50-400nim/year

0-1500 high high Salidy toclayey


Zijphre., .rpitia-cliristi high 50-700nimlyear

0-1500 high hioli., sandy toclayey

high relatively smallqUalltitit'S

Table 10 Land suitability classes for arable crops and tree species cultivated under irrigation

38

Crop am] treespecies

Soil unit

Cereals (sorghum,millet . etc.)

Vegetables (tomatoes,potatoes, water melon,

sweet melon, beans,okra, etc.)

Date palm(Hyphaene thebaica)

Woodland speciese.g. Tamarix nilo-ticaAcacia tortilisZiziphus spina-ch-risti

1

W I I. l

W112 Si Si S2 S3

C 1 13 S2 53 S7 52

Cl 14C 211

C212C221C222C223

S3 S2 Si Si

C111C112

N N S2 S?

Wadi bed N N S3 S2

Chapter 5 CONCLUSIONS AND RECOMMENDATIONS

5.1 CONCI I TSIONS

1. The soil survey carried out in the field and the analytical results show that the soilsof the alluvial plains are generally homogeneous. Most of the soils encountered areslightly developed soils of marine, alluvial and aeolian origin. However, in thecentral alluvial plain, some soils have undergone considerable pedogenetic develop-ment. Certain soils in the alluvial plain, in the areas irrigated by pumped ground-water, have a marked sodium content, either in the soluble form or fixed on theexchan2.e complex.

More generally speaking the soils studied are characterized by

A low organic matter content,- Loamy sand to clay loam textures,

Ivloclerate to good fertility,- Moderately well to well internal drainage,

Localized problems of salinity, associated with well irrigation.

Table 10 lists the mapping units falling into each class of suitability forirrigated agriculture.

The chemical ana/ysis of the underground water around the area revealed that thequality of this water which is used for irrigation is of poor standard, with dominantlyhigh levels of salinity and moderate to high levels of sodium. Also the water analysisfor the sewage treated water indicated that this water has a high salinity and highsodium content (class C4-S4 of the US Salinity Laboratory).

The soil map indicated that about 25% of the area is occupied by active duneland andabout another 35% flat and hummocky sandy areas affected by active sand and windblowing. These areas are used mainly for grazing.

A considerable part of the area (about 40%) is used for traditional rainfed andirrigated farming by the local farmers distributed in their scattered villages around thearea. These include the arable areas (raided and irrigated) oi) flat- sand plain parts.

1.he afforestation effort carried already at a limited northern part of the area and closethe Jayzan road was not successful clue to lack of water for the trees and the treestypes are not suitable for such environment (sand dune fixation in arid climate).

39

5.2 RECOMMENDATIONS

13asecl on the different soil types, topography, activity of wind and sand blowing, thedevelopment plans of the Green I3elt around Hodeiclah should take into consideration the threesignificantly different environments that were identified (see figure 1).

The active dunelancl in which afforestation is highly needed to stabilize the shiftingsands;The irrigated and rainfall arable lands, where there is considerable scope for agro-forestry:Grazing Ian(' that are in urgent need of rehabilitation, which amongst others could beachieved by reafforestation with drought resistant trees and shrubs.

The sewage treated water that is available at the northern side of the survey area couldbe used for afforestation of the sandy active dune lands, which should be planted with selectedtrees tolerant to salinity (e.g. Azadirachta indica). In view of the depletion and decrease inquality of the groundwater reserves, it should be used mainly for irrigation of vegetables andfruit trees, and not for cereal crops. To the extent that the latter can still be grown underfloodwater irrigation, groundwater could be used as a supplementary water source to ensure anacceptable yield level, provided the abstraction for cash crops is not so high that the water tableis adversely affected. There is an urgent need to advice farmers on the judicious use of suchwater for irrigation in order to avoid water wastage through over-irrigation and improperscheduling, while at the same time prevent salinization of the soil.

It is not sufficient to provide a shelterbelt around Hodeidah town, but shelter beltshould also be established to protect agricultural land, provice additional fodder and fuelwood,and support beekeeping activities. It will be necessary to advise the farmers in the area on theimportance of shelter belts. Farmers should also be encouraged to follow proper crop rotationin order to preserve the fertility of the soil. Livestock has to be considered in the rotation bygrowing fodder crops. This will lead to improved soil characteristics, produce fodder andreduce overgrazing.

The creation of recreation areas inside the Green Belt area would particularly benefitthe population of Hodeidah and surrounding villages, but could also be an attraction for touristsfrom other parts of the country, and hence could contribute to local economic activity.

The whole Green Belt area should be conside,red as a protected area supported by strictgovernment laws and regulations to conserve the national resources. An increase in wildlife(animals, birds, etc.) by protection their environment would add to the attractiveness of thegreen belt.. However, without the support of the local population it will not be possible toachieve this. It is therefore imperative that villagers living near the Green Belt be involved inall aspects of the Green Belt: establishment, management, protection etc. This will not onlycreate much needed employment opportunities, but will also contribute to the success of theGreen Belt project.

40

REFERENCES

Acres, 13. '0. 1982. Yemen Arab Republic, Montane Plains and Wadi Rima' Project. Soilclassification and correlation in thc. Montane Plains. Latid Resources Development Centre,Subiton, England. Project Record 72.

Al-Hubaishi, A., and K. Miiller-Hohenstein. 1984. An introduction to the vegetation ofYemen. Ecological basis, floristic composition. human influence. (liTZ, Eschborn.

Anderson, L P. 1979. 'Yemen Arab Republic, Montane Plains and Wadi Rima' Project. Landand Water Resources Survey. Soil survey and irrigation suitability classification of WadiRima'. Land Resources Development Centre, Surbiton, England. Project Record 30.

Bruggeman. H. Y. 1997. Agroclimatic resources of Yemen. Part 1. Agroclimatic inventory.1"A0 project GCP/YEM/021/NET. Field document 11. Renewable Natural ResourcesResearch Centre. AREA, Dhamar.

DM. 1990. Environmental profile Tihama. Environmental Protection Council, Sana'a.Ellatifi, Mohamed. 1996. Guidelines for afforestation with reference to the Republic of 'Yemen,

Gen. Dept. of Forestry and Desertification Control. Min. of Agriculture and WaterResources. Sana'a, Yemen.

FAO. 1995. ECOCROPL Crop Environmental Requirements Database. AGLS, FAO. Rome.FAO. [990. Guidelines for soil profile description. Soil resources, management and conservation

Service. Land and water Division. 3rd Edition (Revised). FAO, Rome.FAO/Unesco. 1988. Soil map of the world, 1:50,000. Revised Legend. FAO, Rome.King, Jack W. II, Terence R. Forbes, Abdul Elah Abu Ghanem. 1983. Soil survey of

Yemen. Yemen Arab Republic. Final report for the Near East Bureau, U.S Agency forInternational Development. Dept. of Agronomy, Cornell University, Ithaca.

SOGREAH. 1981. Wadi Siham Feasibility Study. Final report, Water and Soil Resources.Sogreah Consulting Engineers, Grenoble, France. Volume 1.

Soil Taxonomy Staff. 1994. Keys to Soil Taxonomy. Sixth Edition. United States Dept. ofAgriculture. Soil Conservation Service. Washington D.C.

Van der Gun, J. 1996. The Water Resources of Yemen. SUMMary and digest of availableinformation. TNO Institute of Applied Geosciences. Report WRAY-35. TNO, Delft.

41

APPENDIX 1

SOIL P1«)FILE DESCRIMONS

and

ANALYTICAL DATA

Appendix 1 - page 2

The description of the soil profile is based on field observations. In particular the texture of thevarious horizons does therefore not necessarily correspond to the particle size distribution as givenin the analytical data.

Profile codeAuthor(s)LocationSoil classification

Soil moisture regimeTopographyLand useCropsParent materialSealing/crustingDrainage

HUD050 Date : 29/9/1996M.H. Al-Mashreki and L.K. Al-Asbalii Toposheet : 1442 B2see soil map Elevation : 15 nisancly, mixed, isohyperthenuic, typic Haplocalcid (Soil Taxonomy)haplic Calcisol (FAO/Unesco 1988)aridicalmost flatdryland farmin2nilmarine depositcrustingwell drained

Soil temp. regimeMicro topographyVe2etationSlopeSurface stonesErosionEffective soil depth

isohyperthemiicshifting sandshrubland0.1-2 %nilstrong>150 cm deep

AC 0 - 15 cm brown (10YR 5/3, moist), pale brown (10YR 6/3, dry) sandy loam; massive structure; hard(dry), very friable (moist); common fine and medium pores; very few fine roots; abrupt, wavyboundary.

Ck 15 - 30 cm brovn (10YR 5/3, moist), pale brown (10YR 6/3, dry) fine sandy loam; very weak, coarse,subangular blocky structure; sli2litly hard (dry), loose (moist); many very fine and fine pores;very few fine roots; common, nodules, fine, spherical, soft, concentration of carbonates; clear,smooth boundary.

C 30 - 140 cm dark grayish brown (10YR 4/2, moist), light broi,vnish gray (10YR 6/2, dry) sandy loam;massive structure; soft (dry), loose (moist); fei.v fine pores; no roots.

Soil physical analysis sheet

Hodeidah Green Belt survey - Profile no. HUD 050 - Date collected 29-09-96

Lab.

No.

Depth

(cm)

Particle size distribution (%) Texture

class>2mm

VCS CS MS FS VFS silt clay

798 0-15 1 22 34 24 11 8 sand

799 5-30 o 2 26 40 12 14 6 sand

800 30-140

1 6 31 30 20 12 0 sand

Soil profile description HUD050 Appendix 1 - page 3

Appendix I - page 4

AREA - RENEWABLE NATURAL RESOURCES RESEARCH CENTRE

Soil chemical analysis sheet


Lab.No.

Depth(cm)

pHF120

1: 1

pHKCI1: 1

pHpaste

EC

(mS/cm)

CaCO3

(g/ kg)

Org.C

(g/ kg)

TotalN

(g/ kg)

C/Nratio

Avail.P

(mg/kg)

798 0-15 10.0 17.3 56.3 4.4 0.42 11 4

799 15-30 10.2 11.9 25.0 1.8 0.56 3 4

800 30-140 10.3 14.7 31.3

Lab.

No.

Depth

(cm)

CEC(cmol/kg) Exch. bases (cmol/kg) BS CaS 04

soil clay Na K Ca Mg (%) (g/kg)

789 0-15 16 10.7 1.3 4.0

799 15-30 18 12.5 0.6 4.9

800 30-140 20 13.9 0.1 6

Lab.

No.

Depth

(cm)

extract) ESP

(%)

SAR

Na K Ca Mg CI CO, HCO, SO

789 0-15 10.0 120.6 97 116

799 15-30 7.0 120.3 69 82

800 30-140 210 1.6 8.0 0.2 117 0.0 7.0 95.8 70 104

_




CI - 35 cm

C2 35 - 85 cm

C3 85 - 125 cm

C4 125 - 150 cm

HUD051M.H. Al-Mashreki and L.K.see soil mapcoarse loamy, mixed, isohyperthermic

: calcaric Regosol (FAO/Unesco 1988): aridic: undulating: dryland farming: nil: marine deposit: slight sealing: well drained

dark yellowish brown (10YR 4/4, moist), light yellowish brown (I0YR 6/4, dry) finesandy loam; moderate, medium, subangular blocky structure; slightly hard (dry), friable(moist); many very fine and fine pores; very few very fine roots; strongly calcareous;clear, smooth boundary.

dark yellowish brown (10YR 4/4, moist), light yellowish brown (10YR 6/4, dry) finesandy loam; weak, fine and medium, subangular blocky structure; soft (dry), very friable(moist); common very fine pores; very few medium roots; strongly calcareous; clear,smooth boundary.

yellowish brown (10YR 5/4, moist), light yellowish brown (10YR 6/4, dry) fine sandyloam; porous massive; soft (dry), very friable (moist); common very fine pores; very fewmedium roots; strongly calcareous; clear, smooth boundary.

yellowish brown (10YR 5/4, moist), very pale brown (10YR 7/4, dry); loamy sand; porousmassive; soft (dry), very friable (moist); common very fine pores; very few very fineroots; extremely calcareous.


DateToposheetElevation

typic Torriorthent (Soil

Soil temp. regimeMicro topographyVegetationSlopeSurface stonesErosionEffective soil depth

: 24/9/1996: 1443 Al

Taxonomy)

isohyperthermicshiftiritz sanddwarf shrubland5-10 %nilstrong>150 cm deep


Lab. Depth Particle size distribution (%) Texture

No. (cm) >2mm

VCS CS MS FS VFS silt clay class

756 0-35 16 40 26 9 7 sand

757 35-85 O 12 5 25 51 6 silty loann

758 85-1 25 o 1 48 22 10 8 sand

759 125-1 50

o 9 46 31 7 6 sand

Appenclix 1 - page 6

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756

1E11758

Depth

(cm)

0-35

35-85

85-125

Mg CO3 HCO3 SO4

ESP

%)MI111111111111111111111.1111111 33 MIN....m................ 40

41

MIMIMilEMI 1 2 5-1 50 1111111111111111111111111111111111 43 IIIIIMIMI 1111111111111111111111111111111111111111111111111

SARSoluble Cations Anions (cmol/1 sa . extrac )

Lab.No.

Depth(cm)

pHH201: 1

pHK CI

1: 1

pHpaste

EC

(mS/cm)

CaC 03

(g/kg)

Org.C

(g/kg)

TotalN

(g/kg)

C/Nratio

Avail.P

(mg/kg)

756 0-35 8.1 0.40 25 6.2 0.19 33 4

757 35-85 7.5 0.84 50

758 85-125 7.6 1.4 15

759 125-150

7.8 1.4 75

Depth

(cm)

CEC(cmol/kg) Exch. bases (cmol/kg) BS CaSO,

soil clay Na K Ca Mg (cyo) (g/kg)

0-35 13 4.3 2.0 6.7

35-85 13 5.2 1.8 8.0

85-125 14 5.7 1.8 6.5

1 25-150

12 5.1 1.8 5.1

Lab.

No.

756

757

758

759

Lab.

No.




A - 20 cm

B 20 - 40 cm

Cl 40 - 80 cm

C2 80 - 140 cm

Lab. Depth

No. (cm)

pale brown (10YR 6/3, moist), brown (10YR 4/3, dry) loamy sand; massive structure; soft(dry), loose (moist); many very fine pores; few fine roots; strongly calcareous; clear,smooth boundary.

pale brown (10YR 6/3, moist), brown (10YR 4/3, dry); loamy sand; moderate mediumsubangular blocky structure; soft (dry), loose (moist); many very fine pores; few very fineroots; moderately calcareous; abrupt, smooth boundary.

brown (10YR 4/3, moist); loamy sand; moderate medium subangular blocky structure; soft(dry), loose (moist); common very fine pores; very few very fine roots; slightly calcareous;abrupt, smooth boundary.

brown (10YR 4/3, moist) very fine sandy loam; single grain structure; soft (dry), loose(moist); common very fine pores; no roots; sliditly calcareous.

>2mm

VCS

1

1

1


Hodeidah Green Belt survey - Profile no. HUD 052 - Date collected 2 09-96

Particle size distribution (%)

CS

1

MS

10

13

16

FS

4

44

51

VFS silt

30

19

22

24

: 21/9/1996: 1443 Al

isohyperthermicshifting sandnil0.5-2 %ni I

strong>150 cm deep

clay

Texture

class

loamy sand

loamy sand

sand

loamy sand

13

17 5

4 5

10 5

744 0-20

745 20-40

746 40-80

747 80-140

HUD052 DateM.H. Al-Mashrelci and L.K. Al-Asbahi Toposheetsee soil map Elevationmixed, isohyperthennic, typic Toripsamment (Soil Taxonomy)calcarie Arenosol (FAO/Unesco 1988)aridic Soil Temp. Regimeundulating Micro topographydryland farming Vegetationnil Slopeaeolian deposits Surface stonesslight sealing Erosionwell drained Effective soil depth

Appendix 1 - page 8



Hodeidah Green Belt survey - Profile no. HUD 052 Date collected 21-09-96

BS

(%)

CaSO4

(g/kg)

1111111111MM

ESP

(%)

5

7

40

20

SAR

Lab.No.

Depth(cm)

pHH20

1: 1

pHKCI

1 : 1

pHpaste

EC

(mS/cm)

CaCO3

(g/ kg)

Org.C

(g/ kg)

TotalN

(g/ kg)

C/Nratio

Avail.P

(mg/kg1

744 0-20 7.3 0.42 28.8 3.6 0.28 13 4

745 20-40 7.6 0.35 3.8

746 40-80 8.0 0.42 1.0

747 80-140 7.9 0.27 2.6

Lab.

No.

Depth

(cm)

CEC(cmol/kg) Exch. bases (cmol/kg)

soil clay Na Ca Mg

744 0-20 12 0.6 2.8 8.6

745 20-40 12 0.8 2.7 8.5

746 40-80 13 5.3 3.8 3.9

747 80-140 13 2.6 3.0 7.4

Lab.

No.

Depth

(cm)

Soluble Cations & Anions (cmo1/1 sat. extract)

Ca Mg Cl CO, HCO3 SO4

744 0-20

745 20-40

746 40-80

747 80-140

Soil profile descriptiol HUD 053 Appe,ndix 1 page 9

Profile codeAuthor(s)LocationClassification.

Soil moisture regimeTopographyLand useCropsParent materialSealing/crustint,*Drainage

A - 12 cm

Ck 12 - 55 cm

C 55 - 150 cm

HUD053M.H. Al-Mashrelci and L.K.see soil mapmixed, isohyperthermic typic Torripsamment (Soil Taxonomy)calcaric Arenosol (FAO/Unesco, 1988)

aridic Soil temp. regimealmost flat Micro topouaphydryland farming Vegetationnil Slope %aeolian deposit Surface stonesnil Eros ionwell drained Effective soil depth



lsohyperthermicmedium hummocksdwarf shrubland

: 0.5 - 2%ni 1

strong>150 cm deep

brown (10YR 5/3, moist), pale brown (10YR 6/3, dry) sandy loam; weak, tine andmedium subanizular blocky; soft (dry), very friable (moist); common very tine pores; fewfine roots; strongly calcareous; clear, wavy boundary.

brown (10YR5/3) moist, pale brown (10YR 6/3, dry) sandy loam; massive structure; soft(dry), very friable (moist); common fine and medium pores; very few very fine roots;strongly calcareous; abrupt, smooth boundary.

brown (10YR 5/3, moist); pale brown (10YR 6/3, dry) sandy loam; massive structure; soft(dry), very friable (moist); common very fine pores; no roots; strongly calcareous.

Lab. Depth Particle size distribution (/o) Texture

No. (cm) >2mm


748 0-12 1 1 8 41 37 9 3 sand

749 12-55 0 0 5 55 34 4 2 sand

750 55-150 0 0 4 46 39 10 1 sand

Date 22/9/1996

Toposheet 1443 AlElevation 40 ni

Appendix 1 - page 10

A ' A WABLE NATURAL RESO'URCES SEARCH CENTRE



Lab.

No.

748

749

750

111. MgCo,11MEIN

ENENNEN..rasmoLab.

No.

748

749

750

(cm)

0-12

12-55

55-150

SO4

Lab.No.

Depth(cm)

pHH20

1 : 1

pHKCI

1: 1

pHpaste

EC

(mS/cm)

CaCO3

(g/ kg)

Org.C

(g/ kg)

TotalN

(g/ kg)

C/Nratio

Avail.P

(mg/kg)

748 0-12 7.7 0.62 7.5 3.6 0.14 26 6

749 12-55 7.6 2.0 2.7

750 55-150 8.2 0.5 4.5

0-12 13 0.4 5.0 7.6

12-55 10 1.5 1.2 7.3

55-150 11 0.4 4.0 6.6

Depth Soluble Cations & Anions (cmol/1 sat extrac ) ESP SAR

Depth

(cm)



(%)

3

15

40

Soil profile description HUD054 Appendix i - page 11


Soil moisture regimeTopoglaphyLand useCropsParent materialSealing/cnistingDrainage

A - 18 cm

Bt 18 - 30 cm

Bk 30 - 40 cm

2C1 40 - 80 cm

2C2 80 - 120 cm

HUD054 Date : 22/9/1996

M.H. Al-Mashreki and L.K. Al-Asbahi Toposheet: 1443 Alsee soil map Elevation : 30 nifine loamy over sandy, mixed, isohypertherm typic Haplargid (Soil Taxonomy)haplic Luvisol (FAO/Unesco, 1988)

aridic Soil temp. regime : isohyperthermicalmost tlat Micro topography : evendryland farming Vegetation : shrublandnil Slope : 0.5 - 2%aeolian deposit Surface stones : nilcrusting Erosion : strongmoderately well drained Effective soil depth : >150 cm deep

brown (10YR 4/3, moist), pale brown (10YR 6/3, dry) silt loam; moderate, fine andmedium subangular and angular blocky; soft (dry), very friable (moist), slightly sticky, nonplastic (wet); common fine pores; few fine roots; strongly calcareous; clear, smoothboundary.

brown (I0YR 4/3, moist), very pale brown (10YR 7/3, dry) silty clay loam; strong, coarseand very coarse subangular blocky; slightly hard (dry), friable (moist), sticky and plastic(wet); few faint clay cutans; many tine and medium pores; few very tine roots; strolMycalcareous; clear, smooth boundary

brown (10YR 4/3, moist), very pale brown (10YR 7/3, dry) silty clay; strong, medium,angular blocky and platy structure; hard (dry), friable (moist) sticky and plastic (wet); fewvery fine pores; very few very fine roots; strongly calcareous; clear, smooth boundary.

grayish brown (10YR 5/2, moist), light gray (10YR 7/2, dry) loamy sand; porous massive:loose (dry); few very fine pores; no roots; moderately calcareous; abrupt, irregularboundary.

dark yellowish brown (10YR4/4, moist), yellowish brown (10YR 5/4, dry) sandy loam;porous massive; loose (dry); many very fine pores; no roots



Lab. Depth Particle size distribution (%) Texture

No. (cm) >2mm


751 0-18 1 1 2 12 66 13 5 sand

752 18-30 1 1 3 13 28 39 1 sandy loam

753 30-40 0 0 0 5 9 55 31 silty clay loam

754 40-80 1 1 13 42 36 6 1 sand

755 80-120 1 2 13 42 30 7 5 sand


AREA - RENEWABLE NATURAL RESO ICES RESEARCH CENTRE



Lab.No.

Depth(cm)

pHH20

1 : 1

pHKCI

1 : 1

pHpaste

EC

(mS/cm)

CaC 03

(g/ kg)

Org.C

(g/ kg)

TotalN

(g/ kg)

C/Nratio

Avail.P

(mg/kg)

751 0-18 8.3 0.94 41.3 4.5 0.42 11 5

752 18-30 8.6 1.1 27.5 8.0 0.42 19 4

753 30-40 8.1 1.3 18.8

754 40-80 7.2 1.8 81.3

755 80-120 8.0 2.3 18.8

Lab.

No.

Depth

(cm)

Soluble Cations & Anions (cmo1/1 sat. extract) ESP

(%)

SAR

Na K Ca Mg CI CO3 HCO SO4

751 0-18 40

752 18-30 76

753 30-40 74

754 40-80 56

755 80-120 19.5 0.26 3.2 1.6 8.6 0.0 1.6 14.4 73

Lab.

No.

Depth

(cm)


soil clay Na Ca Mg (%) (g/kg)

751 0-18 13 5.2 3.4 4.4

752 18-30 16 12.1 3.5 0.4

753 30-40 20 14.7 3.2 2.1

754 40-80 11 6.2 2.0 2.8

755 80-120 11 8.0 2.8 0.2


Soil moisture regimeTopographyLand useCropsParent materialSealing/cntstingDrainage

- 75 cm

Ck 75 - 180 cm



isohyperthermicshiftitu2 sancldwarf shrubland0.5 - 2%nilstrong>150 cm deep

brown (10YR 4/3, moist), brown (10YR 5/3, dry) loamy sand; massive stnicture; soft(dry), loose (moist); common very fine pores; few very tine and fine roots; few, crystals,coarse, irregular, hard, carbonates concentrations; moderately calcareous; clear, wavyboundary.

brown (10YR 4/3, moist), pale brown (10YR 6/3, dry) loamy sand; massive structure; soft(dry), loose (moist); common very fine pores; very few roots; few, coarse, irregular, hard,carbonate concentrations; moderately calcareous.

Lab.

No.

Depth

(cm)


class>2mm

VCS CS MS ES VFS silt clay

801 0-75 0 1 6 58 18 13 4 sand

802 7 5-1 80 0 0 6 67 20 7 0 sand

HUD055 Date : 2/10/1996M.H. Al-Mashreki and L.K. Al-Asbalti Toposheet : 1443 Alsee soil map Elevation : 25 nimixed, isohypertherniic, typic Torripsamment (Soil Taxonomy)calcaric Arenosol (FAO/Unesco 1988)aridic Soil temp. reg,imealmost flat Micro topographydryland farming VeL,etationnil Slopeaeolian deposit Surface stonesnil Erosionwell drained Effective soil depth



AREA - RENEWABLE NATI AL RESOURCES RESEARCH CENTRE



0.2

801

802

0-75

75-180

16

17

25

o 0.5

0.8

1.0

14.5

15.5

CO3

0.0 1.6

4

3


CI

2.5

HCO3 SO4

26.7

ESP

(%)

SAR

2

Lab.No.

Depth(cm)

pHH201: 1

pHKCI

1 : 1

pHpaste

EC

(mS/cm)

CaCO3

(g/ kg)

Org.C

(g/ kg)

TotalN

(g/ kg)

C/Nratio

Avail.P

(mg/kg)

801 0-75 7.7 0.73 32.0 2.6 0.70 4 3

802 75-180 7.3 2.2 42.8

Lab. Depth CEC(cmol/kg) Exch. bases (cmol/kg) BS CaSO4

No. (cm) soil clay Na Ca Mg (%) (g/kg)

Soil profile description HUE 020 Appendix I - page 15


Soil moisture regimeTopographyLand useCropsParent materialSealing/crusting,Drainage

Ap O - 30 cm

Cl 30 - 55 cm

C2 55 - 95 c

Ck 95 - 130 cm

brown (10YR 4/3, moist), brown (10YR 5/3, dry) sandy loam; very weak, fine andmedium subangular blocky; soft (dry), very friable (moist); many very fine and fine pores;few very fine and tine roots; strongly calcareous; clear, smooth boundary.

dark grayish brown (10YR 4/2, moist), brown (10YR 5/3, dry) sandy loam; very weak,fine and medium subangular blocky; slightly hard (dry), friable (moist); many very tineand tine pores; very few very fine roots; strongly calcareous; abrupt, smooth boundary.

brown (10YR 4/3, moist), brown (10YR 5/3, dry), sandy loam; massive structure; soft(dry), very friable (moist); common very fine pores; no roots; very few medium,subrounded rock fragments; strongly calcareous; abrupt smooth boundary.

brown (10YR 4/3, moist), brown (10YR 5/3, dry), sandy loam; massive; soft (dry);common fine pores; no roots; few, coarse, irregular, soft and hard, carbimateconcentrations; strongly calcareous.


Hodeidah Green Beit survey - Profile no. HUE 020 - Date collected 24-09-96


Lab.

No.

Depth

(cm)


class>2mm


760 0-30 0 0 10 25 39 22 4 loamy sand

761 30-55 0 1 12 33 32 16 6 loamy sand

762 55-95 0 1 13 38 28 16 4 loamy sand

763 95-130 0 0 8 37 37 16 2 loamy sand

HUE020 Date : 24/9/ 1 996M.H. Al-Mashreki and L.K. Al-Asbalii Toposheet : 1443 Alsee soil map Elevation : 35 nicoarse loamy, mixed, isohyperthermic, typic Torriorthent(Soil Taxonomy)calcaric Regosol (FAO/Unesco 1988)aridic Soil temp. regime isohyperthertilicalmost flat Micro topography low hummocksmixed dryland and irrigated agriculture Vei.zetation vrasslandcereal crops & vegetables Slope 0.5- 2%marine deposits Surface stones nilcrustino. Erosion ni I

well drained Effective soil depth >150 col deep


AREA - RENEWABLE NATURAL RESOITRCES RESEARCH CENTRE


Hodeidah Green Belt survey - Profile no. HUE 020 - Date collected 24-09-96

CEC(cmol/kg)

soil

Mall 303 1.8 6.8 1111111111111111111111MIME4.7 1.8 IMIINIIIIIIIIIIIIIIIIIIII11.1111.111113 3.6 1111111111.1111111111111111111

1.1111111/1 1.6 8.9 MIMI.IIIIIMIIIIIMIIIIIIIIIINIIIIIIIIIIIIIIIIIIIIII

Mg

BS

(A)

CaSO,

(g/kg)

Exch. bases (cmol/kg)

Lab.No.

Depth(cm)

pHH201: 1

pHKC1

1 : 1

pHpaste

EC

(mS/cm)

CaCO3

(g/ kg)

Org.C

(g/ kg)

TotalN

(g/ kg)

C/Nratio

Avail.P

(mg/kg)

760 0-30 8.2 0.7 15.0 8.9 0.28 32 6

761 30-55 7.8 1.5 6.3

762 55-95 7.7 2.1 12.5

763 95-130 8.0 0.9 12.5

Lab.

No.

Depth

(cm)


(%)

SAR

Na K Ca Mg CI CO HCO3 SO4

760 0-30 28

761 30-55 39

762 55-95 16.5 0.27 4.8 4.4 8.0 0.0 1.8 23.4 96 8

763 95-130 25

Lab.

No.

Depth

(cm)

760 0-30

761 30-55

762 55-95

763 95-130

Soil profile description HUE021 Appendix 1 - page 17

HUE021M.H. Al-Mashreki and L.K. Al-Asbahisee soil mapcoarse loamy, mixed, isohyperthermic, typic Torriorthent (Soil Taxonomy)calcaric Regosol (FAO/Unesco 1988)aridic Soil temp. regime : isohyperthennicalmost flat Micro topography : low hunimocksmixed dryland and irrigated agriculture Vegetation : grasslandcereal crops and vegetables Slope : 0.5 - 2%aeolian sand Surface stones : nilnil Erosion : nilmoderately well drained Effective soil depth : >1.50 cm deep

A O - 33 cm brown (10YR 4/3, moist), pale brown (10YR 6/3, dry); fine sandy loam; weak, medium,subangular blocky; soft (dry), very friable (moist); common very fine pores; many mediumand coarse roots; extremely calcareous; clear, smooth boundary.

Cl 33 - 80 cm brown (10YR 5/3, moist), very pale brown (10YR7/3, dry); loamy coarse sand; massivestructure; soft (dry), very friable (moist); many very fine pores; few fine roots; extremelycalcareous; abrupt, smooth boundary.

C2 80 110 cm brown (10YR 4/3, moist), light yellowish brown (10YR 6/4, clry); loamy coarse sand;massive structure; loose (dry); common very fine pores; few very tine roots; few, medium,subrounded rock fragments; extremely calcareous; abrupt smooth boundary.

Ck 110 - 140 cm brown (10YR 4/3, moist), pale brown (10YR 6/3, dry) fine sandy loamy; moderate,medium, subaugular blocky; slightly hard (dry), friable (moist), slightly sticky, slightlyplastic (wet); common very fine and fine pores; few very fine roots; common, medium,subrounded, rock fragments; common, coarse, irregular, hard, carbonate nodules; extremelycalcareous.



Appen ix I - page

Lab.

No.

P1P Particle size distribution (/o) Texture

class>2mm


764 11 0

0

4

4 29 8

loamy sand

loamy sand765

766 80-110 0 45 38 8 2 sand

767 110-140

1 1 4 20 21 51 2 silty loam

Profile code :

Author(s) :

Location :

Soil classification :

:

Soil soisture regime :

Topography :

Land use :

Crops :

Parent material :

Sealing/crusting :

Drainage :

Date : 24/9/1996Toposheet : 1443A1Elevation : 35 m




Hodeiclah Green Belt survey - Profile no. HUE 021 Date collected 24-09-96

Lab.No.

Depth(cm)

pHH20

: 1

pHKCI

1 : 1

pHpaste

EC

(mS/cm)

CaC 03

(g/ kg)

Org.C

(g/ kg)

TotalN

(g/ kg)

C/Nratio

Avail.P

(nrig/kg)

764 0-33 7.3 3.4 12.5 6.2 2

765 33-80 7.0 10.4 52.5

766 80-110 7.0

767 11 0-1 40

Lab.

No.

Depth

(cm)


(`)/0)

73

SAR

19

Na K Ca Mg Cl CO3 HCO3 SO4

764 0-33 31 0.27 4.0 1.2 32.0 0.0 1.2 3.3

765 33-80 72 0.30 9.6 27.2 45.0 0.0 1.2 62.9 60 17

766 80-110 69 0.27 14.8 38.0 115 0.0 1.4 5.7 40 13

767 110-140

120 0.27 69.2 64.8 50 0.0 1.2 203 5 15

Lab.

No.

Depth

(cm)

CEC(cmol/kg) Exch. bases (cmol/kg) BS CaSO4


764 0-33 14 10.2 2.3 1.5

765 33-80 15 9.0 2.3 3.7

766 80-110 13 4.8 1.0 7.2

767 110-140 16 0.8 1.9 13.3

Soil profile description HUE 022

Profile codeAuthons)LocationSoil classification


AC - 15 cm

Cl 15 - 60 cm

C2 60 - 120 cm

C3 120 - 150 cm




isohypertliermicevengrassland0.5 - 2%nilni I

>150 cm deep

brown (10YR 4.5/3, moist), very pale brown (I0YR 7/3, dry) fine sandy loam; singlegrain; soft (dry), very friable (moist); many very fine pores; very few fine roots; stronglycalcareous; clear, smooth boundary.

brown (10YR 5/3, moist), pale brown (10YR 6/3, dry) fine sandy loam; single grain; soft(dry), very friable (moist); few fine and common very fine pores; very few tine roots;strongly calcareous; clear, smooth boundary.

brown (10YR 5/3, moist), pale brown (10YR 6/3, dry) coarse sandy loam: single grain;loose (dry); few fine and common very fine pores; very few very fine roots; stronglycalcareous; abnipt smooth boundary.

broi,vn (10YR 5/3, moist), light gray (10YR 7/2, dry) coarse sandy loam; single grain;loose (dry); common very fine pores; no roots; strongly calcareous.

Lab.

No.

Depth

(cm)


class>2mm


768 0-15 0 3 13 24 41 17 2 loamy sand

769 15-60 0 1 12 26 48 11 2 sand

770 60-120 0 0 7 23 56 13 1 sand

771 120-150 0 1 14 33 38 12 2 sand

HUE022 Date : 25/9/1996M.H. Al-Mashreki and L.K. Al-Asbahi Toposheet : 1443 Alsee soil map Elevation : 30 nimixed, isohyperthermic, typic Torripsamment (Soil Taxonomy)calcaric Arenosol (FAO/Unesco 1988)aridic Soil temp. regimealmost flat Micro topographymixed dryland and irrigated agriculture Vegetationcereal crops Slopealluvium Surface stonesslight sealing Erosionmoderately well drained Effective soil depth


A* A - 7.ENEWABLE NATURAL RESOU- tCES RESEARCH CENTRE



Lab.

No.

768

769

770

771

Depth

(cm)

0-15

15-60

60-120

120-150

Soluble Cations & Anions (cmo1/1 sat extract)

Na K Ca Mg Cl CO3 HCO3

20 0.35 5.2 6.0 11.4 0.0 1.6

Lab.No.

Depth(cm)

pHH2O

1 : 1

pHKCI1: 1

pHpaste

EC

(mS/cm)

CaCO3

(g/ kg)

Org.C

(g/ kg)

TotalN

(g/ kg)

C/Nratio

Avail.P

(mg/kg)

768 0-15 7.9 0.54 28.4 5.3 0.28 19

769 15-60 7.9 0.95 32.0 4.5 0.28 16 2

770 60-120 7.5 1.20 33.2

771 120-150 7.6 2.39 62.0

Lab.

No.

Depth

(cm)



768 0-15 15 1.8 1.9 11.3

769 15-60 13 4.1 2.0 6.9

770 60-120 10 3.9 3.0 3.1

771 120-150 13 3.7 2.7 6.6

ESP SAR

SO4 (%)

12

32

39

18.6 28 9

Soil profile description flUE 023 Appendix 1 - page 21


Soil moisture regimeTopographyLand useCropsParent materialSealing/cnistingDrainage

Ap 0 - 20 cm

(Soil Taxonomy)

isohyperthermicshifting sandsgrassland0.5 - 2%nilmoderate>150 cm deep

dark grayish brown (10YR 4/2, moist), brown (10YR 5/3, dry) sandy clay loam; massivestructure; loose (dry), slightly sticky and slightly plastic (wet); many very fine and finepores; common medium roots; slightly calcareous; clear, smooth boundary.

Btl 20 - 50 cm very dark grayish brown (10YR 3/2, moist), brown (1.0YR 5/3, dry) loan'; weak fine andmedium subangular blocky; soft (dry), very friable (moist), slightly sticky (wet); commonprominent clay cutans; many medium pores; common fine roots; slightly calcareous;abrupt, irregular boundary.

Bt2 50 - 100 cm very dark brown (10YR 2/2, moist) sandy clay loam; weak, fine and medium subangularblocky stnicture; slightly hard (dry), very friable (moist), slidilly sticky and slightly plastic(wet); connuon, prominent clay entails; common medium pores; few fine roots; moderatelycalcareous; gradual, irregular boundary.

B 100 - 120 cm dark brown (10YR 3/3, moist), brown (10YR 4/3, dry) very fine sandy loam; weak tomoderate, meditun subangular blocky stnicture; slightly hard (dry), very friable (moist);many distinct clay cutans; many, medium pores; nil roots; non calcareous.



Lab.

No.

Depth

(cm)

Particle size distribution %) Texture

class>2mm

VCS CS MS ES VFS silt clay

772 0-20 o 2 14 34 43 6 sandyloam

773 20-50 0.0 3 17 18 25 36 1 sandyloam

774 50-100

775 100-120

HUE023 Date : 25/9/1996M.H. Al-Mashreki and L.K. Al-Asbalti Toposheet : 1443 A3see soil map Elevation : 30 nicoarse loarny, mixed, isohyperthermic, typic Torriorthentcalcaric Regosol (FAO/Unesco 1988)aridic Soil temp. regimealmost flat Micro topographymixed dryland and irrigated agriculture Vegetationcereal crops Slopealluvium Surface stonesnil Erosionwell drained Effective soil depth


AREA - RENEWABLE NAT AL RESOURCES RESEARCH CENTRE



Lab.No.

Depth(cm)

pHH20

1 : 1

pHK CI

1: 1

pHpaste

EC

(mS/cm)

CaCO3

(g/ kg)

Org.C

(g/ kg)

TotalN

(g/ kg)

C/Nratio

Avail.P

(mg/kg)

772 0-20 6.6 11.8 24.8 12.5 0.28 45 2

773 20-50 6.9 6.0 29.6 20.5 0.14 146 4

774 50-100 6.5 5.9 27.2

775 100-120 6.6 4.0 24.8

Lab.

No.

Depth

(cm)


(/o)

SAR

Na K Ca Mg CO, HC SO4

772 0-20 65 0.65 22.4 55.6 9.8 0.0 2.0 132.9 54 10

773 20-50 54 0.40 11.6 I I I 47.2 65 15

774 50-100 55 0.30 6.5 I I S 1.4 73.6 86 17

775 100-120 37 0.19 5.2 7.6 26.0 0.0 1.4 22.6 71 15

La b.

No.

Depth

(cm)

CEC(cmol/kg) Exch. bases (cmolikg) BS

( °A)

CaSO,

(g/kg)soil clay Na Ca9.1101

Mg

772 0-20 16 8.6 3.6 3.8

773 20-50 16 10.4 4.0 1.6

774 50-100 14 12.1 3.4

775 100-120 14 9.9 2.4 1.7

Profile codeAnalogs)LocationSoil classification


Cl - 20 cm

C2 20 - 50 cm

C3 50 - 80 cm

Ck 80 - 140 cm

HUE024M.H. Al-Mashreki and L.K. Al-Asbahisee soil mapcoarse loamy, mixed, isohyperthermic,calcic Fluvisol (FAO/Unesco 1988)aridicalmost flatmixed dryland and irrigated agriculturecereal cropsalluviummoderate sealingwell drained




isohyperthennicevengrassland0.5 - 2%nilmoderate>150 cm deep

brown (10YR 4/3, moist), pale brown (10YR 6/3, dry) sandy loam; massive structure; soft(dry), loose (moist); common very fine pores; common medium roots; strongly calcareous:clear, wavy boundary.

brown (10YR 4/3, moist), brown (10YR 6/3, dry) sandy loam; massive stnicture; soft(dry), loose (moist); common very fine pores; few fine roots; strongly calcareous; clear,wavy boundary.

grayish brown (10YR 5/2, moist), light gray (10YR 7/2, dry) sandy loam; massivestructure; loose (dry); common very fine pores; very few fine roots; very few medium,subrounded rock fragments; extremely calcareous; abrupt, irregular boundary.

gray (10YR 5/1, moist), light gray (10YR 7/1, dry) coarse sandy loam; massive structure;loose (dry); common very fine pores; no roots; many medium, rounded rock fragments;conurion coarse hard, irregular carbonate concretions; extremely calcareous.

Lab.

No.

Depth

(cm)


class>2mm


776 0-20 4 26 22 23 23 1 loamy sand

777 20-50 1 13 32 23 16 14 1 sand

778 50-80 5 15 55 17 4 3 sand

779 80-140 5 15 53 17 4 5 sand

Soil profile description HUE 024 Append ix I - page 23

Date : 25/9/1996Toposheet : 1443 A3Elevation : 20 ni

typic Torrifluvent (Soil Taxonomy)





Lab.No.

Depth(cm)

pHH20

1 : 1

pHKCI1: 1

pHpaste

EC

(nnS/cm)

CaCO3

(g/ kg)

Org.C

(g/ kg)

TotalN

(g/ kg)

C/Nratio

Avail.P

(mg/kg)

776 0-20 7.2 0.51 21.2 4.5 0.0 0 1

777 20-50 7.2 0.70 10.0 5.3 0.14 38 2

778 50-80 6.9 5.1 4.0

779 80-140 7.2 2.9 62.0

Lab.

No.

Depth

(cm)



776 0-20 13 3.1 0.38 9.5

777 20-50 10 4.0 0.38 5.6

778 50-80 12 3.1 0.38 0.52

779 80-140 11 1.6 0.36 9.0

Lab.

No.

Depth

(cm)


(%)

SAR

Na K Ca IV19 Cl CO, HCO3 SO

776 0-20

6.01.111111.11=1

3.6 25.4 0.0

24

777 20-50

2.4

40

778 50-80 50 0.3 42.1 26 16

779 80-140 21.5 0.3 4.0 6.4 21.8 0.0 1.8 8.6 9


Soil moisture regimeTopographyLand useCropsParent materialSealing/crustingDrainne

HUE025M.H. Al-Mashreki and L.K. Al-Asbahisee soil mapcoarse loamy, mixed, isohyperthennic,calcaric Regosol (FAO/Unesco 1988)nichealmost flatmixed dryland and irrigated agriculturecereal cropsalluviumcrustingmoderately well drained

Ap O - 10 cm dark brown (10YR 3/3, moist), brown (10YR 5/3, dry) silt loam; moderate, medium,subangular blocky; soft (dry), very friable (moist), sticky and plastic (wet); many fine andmedium pores; many fine roots; strongly calcareous; clear, smooth boundary.

BO 10 - 40 cm brown (10YR 4/3, moist), pale brown (10YR 6/3, dry) clay loam; moderate,medium, subangular blocky; slightly hard (dry), friable (moist), sticky and plastic (wet);very few, faint, clay-humus cutans on pedfaces; common fine and medium pores; few fineroots; few fine soft calcareous filaments; stron0y calcareous; gradual, smooth boundary.

Bt2 40 - 120 cm dark yellowish brown (10YR 3/4, moist), pale brown (10YR 6/3, dry) clay loam; moderateand strong, medium and coarse subanl.*.ular blocky; slightly hard (dry), friable (moist),sticky and plastic (wet); common, distinct, clay-humus cutans on pedfaces; many mediumand coarse pores; very few very fine roots; few fine soft calcareous filaments; stronglycalcareous.

Soil sh sical anal sis sheet

Date : 24/9/1996Toposheet : 1443 A3Elevation : 15 ni

typic Torriorthent (Soil Taxonomy)

Soil temp. regimeMicro topographyVegetationSlopeSurfitce stonesErosionEffective soil depth

isohyperthermicevendwarf slintbland0.5 - 2%nilnil>150 cm deep



Lab.

No.

Depth

(cm)


class>2mm


780 0-10 o o 1.0 4.0 19.0 55.0 21.0 siltloam

781 10-40 o 1.0 1.0 5.0 17.0 51.0 25.0 siltloam

782 40-120






Lab.

No.

780

781

782

Depth

(cm)

0-10

10-40

40-120

CEC(cmol/kg)

soil

12

13

18

clay Na

19.1

11.8

17.8

Exch. bases (cmol/kg)

0.8

0.7

0.8

Ca

0.5

Mg

BS

(%)

CaSO4

(g/kg)

Lab.No.

Depth(cm)

pHH201: 1

pHKCI

1 : 1

pHpaste

EC

(mS/cm)

CaCO3

(g/ kg)

Org.C

(g/ kg)

TotalN

(g/ kg)

C/Nratio

Avail.P

(mg/kg1

780 0-10 6.6 30.9 74 10.6 0.70 15 4

781 10-40 6.7 12.1 36.8 13.4 0.56 24 2

782 40-120 6.7 11.7 32.0

Lab. Depth Soluble Cations & Anions (cmol/1 sat extrac 1 ESP SAR

No. (cm) EIRE= Mg CO, HCO SO4 (%)

780 0-10 MINIIMIMI 59

781 10-40 100 0.24 14.4 24.4 25.4 0.0 2.2 111.8 91 23

782 40-120 100 0.2 13.2 25.6 32.8 0.0 2.2 104 99 23



isohyperthermiclow hummocksdwarf shrubland0.5 - 2%nilstrong>150 cm deep

HUE026 Date : 25/9/1996M.H. Al-Mashreki and L.K. Al-Asbalii Toposheet : 1443 A3see soil map Elevation : 20 ni


Lab.

No.

Depth

(cm)


class>2mm


783 0-30 0.0 16 41 27 11 4 sand

784 30-85 0.0 15 47 20 15 2 loamy sand

785 8 5-140 0.0 14 45 26 10 sand


Cl- 30 cm brown (10YR 4/3, moist), pale brown (10YR 6/3, dry) loamy sand; massive structure; soft(dry), loose (moist); common very fine and fine pores; few very fine roots; extremelycalcareous; abrupt, irregular, boundary.

C2 30 - 85 cm brown (10YR 4/3, moist), pale brown (10YR 6/3, dry) loamy sand; massive structure; soft(dry), loose (moist); conunon very fine and fine pores; very few very fine roots;moderately calcareous; abrupt irregular boundary.

C3 85 - 140 cm brown (10Y 4/3, moist), brown (10YR 5/3, dry) loamy sand; massive structure; soft (drY).loose (moist); common fine pores; few fine roots; slightly calcareous


mixed, isohyperthennic, typic Torripsarnment (Soil Taxonomy)calcaric Arenosol (FAO/Unesco 1988)aridic Soil temp. regimealmost flat Micro topographymixed dryland and irrigated agriculture Vegetationcereal crops Slopealluvium Surface stonesmoderate sealing Erosionmoderately well drained Effective soil depth

Lab.No.

Depth(cm)

pHH20

1 : 1

pHKC1

1 : 1

pHpaste

EC

(mS/cm)

CaCO3

(g/ kg)

Org.C

(g/ kg)

TotalN

(g/ kg)

C/Nratio

Avail.P

(mg/kg)

783 0-30 6.8 3.8 27.2 5.3 0.42 13 4.0

784 30-85 7.5 3.4 8.8 1.8 0.0 0 4.0

785 85-140 7.5 1.9 18.7

Lab.

No.

Depth

(cm)

CEC(cmol/kg) Exch. bases (cmol/kg) BS

(%)

CaSO,

(g/kg)soil clay Na K Ca Mg

783 0-30 16.

3.2 0.7 2.1

784 30-85 13 2.9 1.0 9.1

785 85-140 14 3.4 1.3 9.3

Lab.

No.

Depth

(cm)

Soluble Cations & Anions (cmo1/1 sat extract) ESP

C/01

SAR

Na K Ca Mg Cl CO2 HCO3 SO4

783 0-30 27.5 0.4 2.2 11.7 20 11

784 30-85 31.5 0.5 1.4 18.9 10 13

785 85-140


Ak A - RENEWABLE NAT AL RESOURCES RESEARCH CENTRE



Soil profile description HUE 027 Appendix 1 - page 29


Soil moisture regimeTopographyLand useCropsParent materialSealing/crustingDrainne

AB - 15 cm

Bk 15 - 45 cm

Ck 45 - 75 cm

C 75 - 120 cm

dark brown (10YR 3/3, moist); brown (10YR 4/3, (lry) sandy loam; weak and moderate,medium and coarse, subangular blocky; hard (dry), very friable (moist); many fine andmedium pores; very few fine roots; slightly calcareous; clear, smooth boundary.

brown (10YR 4/3, moist), pale brown (10YR 6/3, dry) sandy clay loam; moderate mediumand coarse subangular blocky; soft (dry), very friable (moist); many fine and mediumpores; very few very fine and fine roots; common tine, spherical, soft, carbonate nodules;moderately calcareous; gradual, wavy boundary.

dark yellowish brown (10YR 3/4,1noist), pale brown (10YR 6/3, dry) sandy loam; veryweak, medium, subanallar blocky; soft (dry), loose (moist); many very fine to fine pores;very few very fine roots; common fine, irregular, soft, carbonate nodules; extremelycalcareous; clear, smooth boundary.

brown (10YR 5/4, moist), very pale brown (10YR 7/4 dry) loamy sand; massive structure:soft (dry), loose (moist); many very fine pores; no roots; very few fine, spherical, soft,carbonate nodules; extremely calcareous.



Lab.

No.

Depth

(cm)


class>2mm


786 0-15 0.0 3 13 20 23 33 8 sand loam

787 15-45 0.0 2 9 23 28 36 2 sand loam

788 45-75 0.0 2 5 24 33 34 2 sand loam

789 75-120 0.0 2 5 15 27 51 0 silt loam

HUE027 Date : 30/9/1996M.H. Al-Mashreki and L.K. Al-Asbalii Toposheet : 1442 B4see soil map Elevation : 15 nicoarse loamy, mixed, isohyperthermic, typic Haplocalcid (Soil Taxonomy)haplic Calcisol (FAO/Unesco 1988)aridic Soil temp. regime isohyperthermicalmost flat Micro topotzraphy lol,v hummocksnil Vegetation dwarf shrublandnil Slope 0.5 - 2%alluvium Surface stones nilmoderate sealing, Erosion ni I

moderately well drained Effective soil depth >150 cm deep


A A - RENEWABLE NAT AL RESOURCES RESEARCH CENTRE



Lab.No.

Depth(cm)

pHH201: 1

pHKCI

1 : 1

pHpaste

EC

(mS/cm)

CaCO3

(g/ kg)

Org.C

(g/ kg)

TotalN

(g/ kg)

C/Nratio

Avail.P

(mg/kg)

786 0-15 7.1 80.7 10.0 7.0 0.14 50 5

787 15-45 6.7 61.3 37.5 6.2 0 0 2

788 45-75 6.7 55.8 40.8

789 75-120 6.9 37.6 25.0

Lab.

No.

Depth

(cm)


(%)

CaSO,

(g/kg)-

soil clay Na K Ca Mg

786 0-15 26 16 0.6 9.4

787 15-45 19 4.4 0.2 14.4

788 45-75 17 5.1 0.1 11.8

789 75-120 21 8.9 0.0 12.1

Lab.

No.

Depth

(cm)


(%)

SAR

Na K Ca Mg Cl CO, HCO3 SO4

786 0-15 960 1.1 134 18.0 8.6 0.0 1.0 1103.4 57 110

787 15-45 620 0.4 296 42.0 11.6 0.0 1.0 945.8 13 48

788 45-75 540 0.2 262 68.0 10.6 0.0 1.0 858.7 14 42

789 75-120 370 0.1 168 28.0 10.6 0.0 1.2 554 32 37


Soil moisture regimeTopographyLand useCropsParent materialSealing/cnistingDrainage

A 0 - 10 cm

B 10 - 30 cm

Cl 30 - 80 cin

C2 80 - 150 cm




Taxonomy)

isohyperthermichigh hummocksdwarf shrubland0.5 - 2%nilnil>150 cm deep

brown (10YR 4/3, moist), pale brown (10YR 6/3, dry) coarse loamy sand; massivestructure; loose (dry), very friable (moist); many very fine pores; few very tine roots;moderately calcareous; clear, smooth boundary.

dark yellowish brown (10YR 4/4, moist), brown (10YR 5/3, dry) tine sandy loam;moderate and strong, medium and coarse, subangular blocky; hard (dry), friable (moist);common fine and medium pores; few very fine roots; strongly calcareous; clear, smoothboundary.

dark grayish brown (10YR 4/2, moist), brown (10YR 5/3, dry) coarse sandy loam; veryweak, fine, subangular blocky; soft (dry), loose (moist); common fine and medium pores;very few very fine roots; many, fine and medium, spherical and irregular, soft carbonatesegregations; moderately calcareous; gradual, wavy boundary.

brown (10YR 5/3, moist), lit-iht gray (10YR 7/3, dry) coarse sandy loam; massive stnicture;soft (dry), loose (moist); few very fine and fine pores; no roots; few, fine, spherical andirregular, soft, carbonate segreilations; extremely calcareous.

Lab.

No.

Depth

(cm)

Particle size distribution (°/0) Texture

class>2mm


790 0-10 0 1 23 34 23 19 0 loamy sand

791 10-30 1 3 21 21 14 34 6 sandy loam

792 30-80 0 3 31 31 14 21 0 loamy sand

793 80-150 0 2 26 41 13 16 2 loamy sand

HUE028 Date : 30/9/1996M.H. Al-Mashreki and L.K. Toposheet : 1442 B4see soil map Elevation : 10mcoarse loamy, mixed, isohyperthermic, typic Haplocalcid (Soilhaplic Calcisol (FAO/Unesco 1988)aridicalmost flatmixed dryland and irrigated agriculturecereal cropsmarine depositnilmoderately well drained

Soil profile description HUE 028 Appendix 1 - page 31


A A - RENEWABLE NATURAL RESOURCES RESEAtCH CENTRE



Lab.

No.

Depth

(cm) =MIEN Mg

12.8

9.6

CO,

o

o

O

SO4

ESP

CYO

SAR

1=11111111MMIIIMINIII= =ENO=


Lab.No.

Depth(cm)

pHH2O

1: 1

pHKCI1: 1

pHpaste

EC

(mS/cm)

CaCO3

(g/ kg)

Org.C

(g/ kg)

TotalN

(g/ kg)

C/Nratio

Avail.P

(mg/kg)

790 0-10 7.0 20.4 55.0 13.2 0.42 31 2

791 10-30 7.1 37.2 75.0 1.8 0.70 3 10

792 30-80 7.0 38.4 18.8 6.2

793 80-150 6.9 46.3 25.0 7.0

Lab.

No.

Depth

(cm)


(%)

CaSO,

(g/kg)soil wil K Mg

790 0-10 9 11.1 3.0 1.0 111111=11111=791 10-30 18 MI 6.9 min 9.6 =EMI792 30-80 16 ..1 8.6 0.9 6.5 III=MI793 80-150 17 NM= 0.2 liniMM EOM

IMIM.111=1 IMO= ME

790 0-10 180 70 24

791 10-30 380 4.5 140 38

792 30-80 470 2.0 96 36

793 80-150 490 0.7 166 74

1.8 269 10 26

1.0 550 30 40

1.0 590 32 68

1.6 791.5 60 45

11.6 o



A - 10 cm

Cl 30 - 65 cm

C2 65 - 120 cm

yellowish brown (10YR 5/4, moist), very pale brown (10YR 7/4, dry) tine sandy loam:weak, medium, subangular blocky; soft (dry), very friable (moist); common very fine andfine pores; very few very fine roots; strongly calcareous; clear, smooth boundary.

yellowish brown (10YR 5/4, moist), very pale brown (10YR 7/4, dry) sandy loam; weak,medium, subangular blocky; hard (dry), very friable (moist); common fine and mediumpores; few fine roots; slightly calcareous; clear, smooth boundary.

dark yellowish brown (I0YR 4/4, moist), yellowish brown (10YR 5/4, dry) sandy loani;porous massive; soft (dry), very friable (moist); common very fine pores; few very tineroots; very few, fine, irregular, soft carbonate segregations; non calcareous; clear smoothboundary.

yellowish brown (10YR 5/4, moist), light yellowish brown (10YR 6/4, dry) sandy loam;porous massive stnicture; soft (dry), very friable (moist); common very fine pores; noroots; moderately calcareous.


Texture

class

loamysand

loamysand

loamysand

sand


Lab.

No.

Depth

(cm)

Parti le size di stribution (%)

>2mm


794 0-10 o 2 26 41 13 16 2

795 10-30 o 1 13 42 18 26 o

796 30-65 o 1 12 47 20 18 2

797 65-120 O 1 12 48 19 14 4

Soil profile description HUE 029 Appendix 1 - pa.ge 33

HUE029 Date : 30/9/1996M.H. Al-Mashreki and L.K. Al-Asbahi Toposheet : 1442 B4see soil map Elevation : 10 mcoarse loarny, mixed, isohyperthennic, typic Torriorthent (Soil Taxonomy)calcaric Regosol (FAO/Unesco 1988)aridic Soil temp. regime : isohyperthermicalmost flat Micro topography : high hummocksdryland fanning Vegetation : dwarf shrublandnil Slope : 0.5 - 2%marine deposits Surface stones : nilnil Erosion : moderatemoderately well drained Effective soil depth : >150 cm deep

AC 10 - 30 CM





Lab.No.

Depth(cm)

pHH20

1 : 1

pHKCI

1 : 1

pHpaste

EC

(mS/cm)

CaCO3

(g/ kg)

Org.C

(g/ kg)

TotalN

(g/ kg)

C/Nratio

Avail.P

(mg/kg)

794 0-10 6.7 17.8 50.0 4.4 7

795 10-30 6.5 27.4 12.5 2.6 0.56 5 2

796 30-65 6.6 23.2 50.0 5.3

797 65-120 6.7 31.8 113.8 3.5

Lab.

No.

Depth

(cm)

Soluble Cations & Anions (cnno1/1 sat. extract) ESP SAR

Na K Ca Mg Cl CO,

794 0-10 240 3.1 20 6 260 0.0 0.5 8.6 36 67

795 10-30 310 52

796 30-65 300 60

797 65-120 360 1.6 92 14 370 0.0 2.2 95.4 79 49

Lab.

No.

Depth

(cm)


(0/0)

CaSO,

(9/kg)soil clay Na Ca Mg

794 0-10 15 o 5.4 2.7 6.9

795 10-30 17 o 7.1 2.5 7.4

796 30-65 17 12 9.6 1.5 7.9

797 65-120 14 29 10.9 1.2 1.9

Soil profile description HUE 030 Appendix I mge 35


Soil moisture regimeTopographyLand useCropsParent materialSealing/crustim;Drainage

A 0 - 30 cm

Cl 30 - 60 cm

C? 60 -100 cm

brown (10YR 5/3, moist and dry) sandy loam; very weak, coarse and very coarsesubangular blocky; loose (dry), very friable (moist); common very tine and fine pores; fewvery fine roots; moderately calcareous; clear, smooth boundary.

light yellowish brown (10YR 6/4, moist), dark yellowish brown (10YR 4/4, dry) sandyloam; massive structure; loose (dry), very friable (moist); many very tine and fine pores;few very fine roots; strondy calcareous; clear, smooth boundary.

yellowish brown (10YR 5/4, moist), brown (10YR 4/3, dry) sandy loam; massivestructure; loose (dry), very friable (moist); many very fine and fine pores; no roots;common, medium, irregular soft carbonate segregations; extremely calcareous

HUE030 Date : 12/9/1996M.H. Al-Ivlashreki and L.K. Al-Asbalii Toposheet : 1443 A3see soil map Elevation : 20 nitine loamy, mixed, isohyperthermic, typic Torriorthent (Soil Taxonomy)calcaric Regosol (FAO/Unesco 1988)aridic Soil temp. regime isohyperthermicalmost flat Micro topography evenmixed drylancl and irrigated auiculture Vegetation shrublandcereal crops and cotton Slope 0.5 - 2%aeolian deposit Surface stones nilnil Erosion nil

well drained Effective soil depth >150 cm deep

APPENDIX 2

ANALYTICAL WATER DATA

Appendix 2- Page 37

WATER ANALYSIS RESULTS

SAR: Sodium Adsorption Ratio RSC: Residual Sodium Carbonate ESP: Exchangeable Sodium Percentage

Classification (U.S. Salinity Lab.):

S4-C4 = Very high salinity, very high sodium. Not suitable for irrigation except under very special circumstances of excellentdrainage and for very tolerant crops.

S4-C3 = Very high salinity to high sodium water. This water is not suitable for irrigation under ordinary conditions and mayproduce harmful levels of both salts and alkali in most soil except under very special soil and crop management.

S4-C2 = Very high salinity medium sodium water. Not suitable for irrigation but can be used for reclamation of highly salinesoils provided that the E.C. of the soil at saturation is grater than E.C. of this water.

W.S.NO

E.C.m

S/cm

at 25C

pH SUM OFCATIONS cmUL

Co3 HCO3 SO4 SUM OFANIONcml/L

SAR RSC ESP USDACLASS

4.19 7.8 42 0.1 5.4 50.7 0.0 2.0 2.8 45.9 50.7 20 0.0 82.8 C4-S4

MI 4.55 =FM 0.1 56.6 0.0 2.4 26 28.2 56.6 IBM 0.0 65 C4-S3

3 EMI 7.6 0.1 3.4 6.4 35.9 0.0 3.4 9.0 35.9 liell 0.0 im C4-S4

4 4.6 MN 28 0.2 10 49.2 0.0 2.8 43.9 49.2 9 0-0 MEE=MI 3.9 8 IME 0.2 9.1 9.4 44.7 0.0 3.4 1.4 39.9 44.7 9 0.0 58 C4-S3

6 11111113111= 0.2 15 23.8 86 0.0 3.4 3.8 78.8 86 Mill 0.0 INIMIIIMI8.8 63 0.2 8.6 20.4 86 0.0 1.4 50.4 40.8 EMI 4 0.0 6.8 IBIZEM

8 9.1 7.4 67 0.2 14.1 Es 107.2 0.0 2.0 60.0 45.2 107.2 ER 0.0 63 C4-S4

111.1 10.1 7.4 0.2 Egm 36.5 118.2 0.0 2.0 70.0 48.0 118.2 KM 0.0 EMI C4-54

DIEEIMIIM 24 0.1 EMI 6.2 IMO= 0.0 2.4 10.0 20.9 IIMME11. 0.0 68 C4-S3

KM 43 1711111111111 4.3 IgilIMMIE 0.026 19.1 56.1 mum 0.0 C4-S4

Appendix 2- page38

Water samples were taken from sites as indicated below:

Water sampleNO.

Location Well Depth(M)

NearestOpservation

1 Al- oga Village 60 Profile no. HUD0532 Biot Al- Offa Village loo Profile no. HUDO543 Deer Hassan 50 Profile no. HUE0204 Mahal Al- Shaika Profile no. HUE0215 Al-Sharaf Al- A'ala V Augering. no. 126 Al- Zafaran Village

Al- Guraiba VillageAl- Se a'a Village

405050

Augering. no. 137 Profile no. HUE024

Profile no. HUE0288

9 N Quzat Al-Dubal N 50 P ofile no. HUTEO260 AL-13 ayda Water s ation

Sewage Water


HUDEIDA GREEN BELT SOIL SURVEY_COMMENT ON RESULTS OF ANALYSIS

"REQUESTED BY MR. AL-MASHREKI"

A.E. FADL (SOIL CHEMIST)

The soil of the surveyed area are coarse to moderately coarse textured soils.

Textural classes are dominantly loamy sand, sand and sandy loam. This may

critically increase the downward movement of water to undesirable rate, a-nd

gravity irrigation may present some difficulties, particularly at the sand textured

sites where contents of both silt and clay are very lovv. F-lowever, other

characteristics are involved in the movement and percolation of water such.as

condition of the soil surface, sodicity status and quantity and quality of soluble

salts. It is strongly recommended that special water management practices, that

consider the above mentioned criteria be followed in this area.

The area is variably affected by soluble salts. 9 of the 16 sampled sites are

non-saline vvith an average E.C. at saturation less than 4 mS/cm. However at all

other sites salinity levels are sufficiently high to affect adversely the growth of

most plants. Sulfate and chloride are the principal soluble anions present in these

soils, the bicarbonate content is relatively lovv and carbonate is absent. Soluble

sodium content exceeds those of calcium plus magnesium, and thus the high SAR

values. Saline areas are generally sodic. Accordingly both leaching and replacement

of exchangeable sodium are required for reclamation, and irrigation agriculture

would have doubtful success at areas represented by profiles HUED23, 25, 27, 28,

29 and HU0003 unless reclamation measures are carried out.

CaCO3 is a comn-ion constituent of all sampled sites. Its content varies

between 2-8%. Presence of gypsum is also evidenced by high concentration of

both soluble calcium and sulfate in saturation extract, and by a relatively low pH

(commonly less than 8.2) in presence of high sodicity levels. The two constituents

together with soluble salt determine the suitability of different amendments and

process of leaching this area.


Conclusion : The soils of Green-Belt area are regarded as problem soils that require

very special remedial measures and management practices. It is unfortunate that

all sources of water available in the area as represented by 11 water sample

analysed in our laboratory are of very high salt content and their use may result in

further salinization. (See lab report an analysis of water samples collected from

Green Belt area).

Appendix 3 - pap..e 41

LABOkATORY ANALYSIS METHODS

All results refer to oven dry soil sieved through 2 m m sieve.

. Soil Reaction (pH) is determined by pH meter.A model WTW pH 422 pH meter is used

2. Total soluble salts (E.C.)Saturation paste is prepared by adding soil to a known quantity ofdistilled water to the saturation point. Saturation extract is suckad.offusing vacuum. E.C. of saturation extract is read off an E.C: modelWTW meter and expressed in mS/cm at 25°C.

Concentration of soluble Na and K are measured by flame photometry

Soluble Ca and Mg are titrated against EDTA.

Soluble CO3 and HCO3 are obtained by titration against standardsulphuric acid using phenolphthalein and methyl orange indicators.

Soluble chloride by titration vvith silver nitrate.

Soluble sulphate is obtained by one of the following three methods

7.1 Gravimetrically by precipitation as barium sulphate.7.2 A modified versenate method.7.3 Colorimetrically, by barium chromate method.

Calcium carbonate : Acid neutralization method is used:

Organic carbon : Modified Walkley - Black method is u.Sed.

Total Nitrogen : Measured according to the standard Kjeldahl methodusing convenient digestion, distillation and titration units supplied byTecator, Svveden.

Available phosphorus : Olsen method (0.5 M sodium bicarbonateextraction).

Cation Exchange Capacity : Saturation of the soil colloidal complex iseffected with IN sodium acetate at pH 8.2 and excess salt is removedwith ethanol. Sodium is then replaced by ammonium, using INammonium acetate at pH 7.0 and concentration of sodium is

determined in the final solution by flame photometry.

Exchangeable cations : Exchangeable Na and K are determined in INammonium acetate leachate. Results are corrected for water solubleNa and K and net exchangeable values are reported. Exchangeable Caand Mg are determined in the same leachate if soils are non-


calcareous, or by difference calculation from CEC in calcareous soils.

14. The following parameters are obtained by direct calculation.

C/N ratioCEC/ClayESPSAR

15. Mechanical Analysis : A modified hydrometer met/loci is used whichinvolves the following three stages

Removal of soluble salts and complete dispersion in calgonSeparation of total sand by wet sieving followed by divisioninto 5 sand components, (USDA) system, by dry sieving.Determination of the clay fraction in the dispersed sample byhydrometer and calculation of silt by difference.

Soils rich in CaCO3 and organic matter are carried out through 'specialtreatment. The fine earth fraction (less than 2 millimetres) is used forthe test, and USDA system of the particle SiZe grade is adopted toexpress results of the different fractions i.e.

Water Retention at 0.033 and 1.5 MPaSaturated soil is placed in closed chamber, subjected to requyedpressure and allowed to stand vvhile water is forced out untilequilbrrium is reached. The moisture content is then determined byoven drying and moisture percentages at field capacity (1.5 MPa) andvvilting point (0.03 MPa) are recorded. Complete set of equipmentsupplied by Soil Moisture Equipment Corp. USA are used for the test.

Non-routine determinations include bulk density, particle density,porosity, liquid limit, plastics limit plasticity index and hydraulicconductivity.

M. Mvery coarse sand 2.0 - 1.0Coarse sand 1.0 - 0.5Medium sand 0.5 - 0.25Fine sand 0.25 - 0.1V. fine sand 0.1 - 0.05Silt 0.05 - 0.002Clay Less than 0.002

Table 4 Soil mapping description

Soil moping units Components of main

and association soilsTopography Slope (/o) Main characteristics

S m ol T e of ma in. unitC 11 Undiffrentiated group Typic Torripsaments

Typic Torriorthents

inclusions

Undulating 5-10 Very deep, well drained,

slightly to moderately calcareous,

sand to loamy sand texture,

massive to subangular blocky structure,

parent material is reworked aeolian sediments,

with surface sealing.

C122 Undiffrentiated group Typic Torripsaments

Typic Torriorthent

Inclusion

Gently undulating 2-5 Very deep, well drained, slightly calcareous,

fine sandy loam to loamy sand texture,massive

structure.

C133 Complex Typic Torriorthents

Typic Torripssaments

Typic Haplargids

Typic Haplocambids

Inclusions

Flat 0-0.5 Very deep, well to excessively drained, slightly

calcareous,stratifide very fine sandy loam to

coarse sand loam and gravely layers below 12(

cmdepth,massive and subangularblocky struci

C144 Consociasion Typic Torripssaments

Typic Torriorthents

Inclusions

Gently sloping 2-5 Deep to very deep, well to moderately

drained, moderately to strongly calcareous

loamy sand to sandy loam texture,massive

structure, the shale found throughout the

profiles.

C211 Comlex TypicTorripsamments

Typic Torriorthents

Typic Torriflufents

Gently sloping 2-5 Deep to very deep, well draind, moderately to

strongly calcareous sandy loamt texture,

massive strucure.

C212 Consociation Typic haplocalcids

Typic Torriorthents

Inclusion

Gently level 0.5-2 Deep to very deep, moderately drained,

moderately to strongly calcareous,sandy loam t

loamy sand texture, subangular blocky structu

C221 Comlex Typuic Torriorthents

Typic Haplocalcids

Typic Torripssamments

Inclusion

Nearly Level 05-2 Very deep, well to moderately drained,

moderately calcareous, sandy loam texture,

massive to subangular blocky structure.

C222 Consociation

Typic Torripsamments

Typic Torriorthents

Inclusions

Nearly level 0.5-2 Deep to very deep, moderately drained,

moderately to strongly calcareous, sandy loam

texture, massive to subangular blocky structure

C223 Consociation Typic Torriorthents


Nearly level 0.5-2 Deep to very deep, well to moderately drained,

moderately to strongly calcareous, sandy loam

texture, massive structure.

W111 Complex Typic Torrifluvents

Typic Torriorthents


Fluventic Haplocambids

Inclusions

Gently sloping 2-5 Very deep, well to moderately drained, strongly

to extremely calcareous, sandy loam texture

subangular blocy structure.

W112 Complex Typic Torriorthents

Typic Torrifluvents


Gently sloping 2-5 Very deep, moderately well drained, strongly

calcareous, silty loam texture

subangular blocy structure.

Documents

Land Resource Study of Hodeidah Green Belt Area. Field … · 2017. 11. 27. · fig. 1 Location map of the study area 3 fig. 2 Generalized geological map of Yemen 4 fig. 3 Flodeidah: